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Translocations are an important tool for the conservation of biodiversity, but although ecological feasibility studies are frequently conducted prior to implementation, social feasibility studies that consider how local communities perceive such projects are less common. The translocation of blue sheep Pseudois nayaur to Sagarmatha National Park, Nepal, has been proposed, to reduce livestock depredation by snow leopards Panthera uncia by providing an alternative prey base in addition to the small population of Himalayan thar Hemitragus jemlahicus. This study used systematic sampling, a quantitative questionnaire and qualitative interviews within the Park to provide data on the social viability of the proposed translocation. Quantitative analysis revealed moderate levels of support but qualitative analysis suggested that there are significant concerns about the proposal. In addition, multiple regression analysis found that women and livestock owners were significantly less supportive, although the model had low explanatory power. Potential crop damage and competition for forage were frequently cited as concerns, especially amongst those with a high level of dependence on natural resources. Given the mixed response to the proposed translocation of blue sheep to the Everest region, alleviating the reservations of local residents is likely to be key to any further consultation, planning or implementation.
The Vulnerable snow leopard Panthera uncia experiences persecution across its habitat in Central Asia, particularly from herders because of livestock losses. Given the popularity of snow leopards worldwide, transferring some of the value attributed by the international community to these predators may secure funds and support for their conservation. We administered contingent valuation surveys to 406 international visitors to the Annapurna Conservation Area, Nepal, between May and June 2014, to determine their willingness to pay a fee to support the implementation of a Snow Leopard Conservation Action Plan. Of the 49% of visitors who stated they would pay a snow leopard conservation fee in addition to the existing entry fee, the mean amount that they were willing to pay was USD 59 per trip. The logit regression model showed that the bid amount, the level of support for implementing the Action Plan, and the number of days spent in the Conservation Area were significant predictors of visitors’ willingness to pay. The main reasons stated by visitors for their willingness to pay were a desire to protect the environment and an affordable fee. A major reason for visitors’ unwillingness to pay was that the proposed conservation fee was too expensive for them. This study represents the first application of economic valuation to snow leopards, and is relevant to the conservation of threatened species in the Annapurna Conservation Area and elsewhere.
Lower prenatal exposure to n-3 PUFA relative to n-6 PUFA has been hypothesised to influence allergy development, but evidence remains largely inconsistent. In the Dutch Maastricht Essential Fatty Acid Birth (MEFAB) (n 293) and Greek RHEA Mother–Child (n 213) cohorts, we investigated whether cord blood phospholipid PUFA concentrations are associated with symptoms of wheeze, asthma, rhinitis and eczema at the age of 6–7 years. Information on allergy-related phenotypes was collected using validated questionnaires. We estimated relative risks (RR) and 95 % CI for associations of PUFA with child outcomes using multivariable generalised linear regression models. In pooled analyses, higher concentration of the n-3 long-chain EPA and DHA and a higher total n-3:n-6 PUFA ratio were associated with lower risk of current wheeze (RR 0·61; 95 % CI 0·45, 0·82 per sd increase in EPA+DHA and 0·54; 95 % CI 0·39, 0·75 per unit increase in the n-3:n-6 ratio) and reduced asthma risk (RR 0·50; 95 % CI 0·31, 0·79 for EPA+DHA and 0·43; 95 % CI 0·26, 0·70 for the n-3:n-6 ratio). No associations were observed for other allergy-related phenotypes. The results were similar across cohorts. In conclusion, higher EPA and DHA concentrations and a higher n-3:n-6 fatty acid ratio at birth were associated with lower risk of child wheeze and asthma. Our findings suggest that dietary interventions resulting in a marked increase in the n-3:n-6 PUFA ratio, and mainly in n-3 long-chain PUFA intake in late gestation, may reduce the risk of asthma symptoms in mid-childhood.
Clinoptilolite modified with polypyrrole and iron oxide nanoparticles (Cln-PPy-Fe3O4) nanocomposite as a potential adsorbent for V (V) ions was prepared via polymerization of pyrrole monomer using FeCl3 oxidant in aqueous medium in which clinoptilolite-Fe3O4 nanoparticles were suspended. The structure and morphology of the prepared adsorbent was analysed with the Fourier transform infrared (FTIR) spectrometer, field-emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and high-resolution transmission electron microscope (HR-TEM). Column fixed bed studies were performed to test the ability of the adsorbent to remove V (V) ions from aqueous solution. Low values of adsorbent exhaustion rate (AER) and large bed volumes were observed at lower metal ion concentration, higher bed mass and lower flow rate for V(V) removal indicating good performance. The volume of treated water processed at breakthrough point were found to be 0.09; 0.63 and 1.26 L for bed mass of 1, 2.5; and 5 g, respectively. The Yoon–Nelson and Thomas models appropriately described the breakthrough curves.
When a millimetre-sized liquid drop approaches a deep liquid pool, both the interface of the drop and the pool deform before the drop touches the pool. The build-up of air pressure prior to coalescence is responsible for this deformation. Due to this deformation, air can be entrained at the bottom of the drop during the impact. We quantify the amount of entrained air numerically, using the boundary integral method for potential flow for the drop and the pool, coupled to viscous lubrication theory for the air film that has to be squeezed out during impact. We compare our results with various experimental data and find excellent agreement for the amount of air that is entrapped during impact onto a pool. Next, the impact of a rigid sphere onto a pool is numerically investigated and the air that is entrapped in this case also matches with available experimental data. In both cases of drop and sphere impact onto a pool the numerical air bubble volume
is found to be in agreement with the theoretical scaling
is the Stokes number. This is the same scaling as has been found for drop impact onto a solid surface in previous research. This implies a universal mechanism for air entrainment for these different impact scenarios, which has been suggested in recent experimental work, but is now further elucidated with numerical results.
A tiny air bubble can be entrapped at the bottom of a solid sphere that impacts onto a liquid pool. The bubble forms due to the deformation of the liquid surface by a local pressure buildup inside the surrounding gas, as also observed during the impact of a liquid drop on a solid wall. Here, we perform a perturbation analysis to quantitatively predict the initial deformations of the free surface of a liquid pool as it is approached by a solid sphere. We study the natural limits where the gas can be treated as a viscous fluid (Stokes flow) or as an inviscid fluid (potential flow). For both cases we derive the spatiotemporal evolution of the pool surface, and recover some of the recently proposed scaling laws for bubble entrapment. On inserting typical experimental values for the impact parameters, we find that the bubble volume is mainly determined by the effect of gas viscosity.
In order to make further progress, particularly in the field of cosmic rays, it will be necessary to apply all our resources and apparatus simultaneously and side-by-side; an effort which has not yet been made, or at least, only to a limited extent.
Victor Francis Hess (1883–1964)
Relativistic compact systems are potential sources of UHECRs and VHE neutrinos. This, of course, requires that a considerable fraction of the dissipation energy will be tapped for acceleration of baryons to ultra-high energies, which poses a great challenge to any model. Nonetheless, this possibility is strongly motivated by the detection of cosmic rays at energies up to ~1020 eV. While cosmic rays below the knee, at energies of <1015 eV or so, are commonly believed to be accelerated by supernovae blast waves, the origin of the cosmic-ray population above the knee and, in particular, the UHECRs, is yet a mystery. Scenarios in which UHECRs and VHE neutrinos are produced in relativistic outflows, particularly GRB or blazar jets, have important implications for the jet content, the dissipation mechanism and, possibly, the physics of inner engines. In contrast to electromagnetic emission that can have either leptonic or hadronic origin, VHE neutrino emission is a unique diagnostic of hadronic content. Hence, their detection will be an important step in our understanding of compact astrophysical systems. Furthermore, it may lead to a firm identification of the mysterious astronomical origin of UHECRs.
Ultra-high energy cosmic rays
Cosmic rays were first discovered by Austrian Victor Hess in his pioneering balloon experiments in 1912. For this discovery, he was awarded the Nobel Prize in Physics 1936.
The virtues, like the Muses, are always seen in groups. A good principle was never found solitary in any breast.
Guatama Buddha (d.o.b. c.486 BC)
In this chapter we shall develop fundamental concepts for describing relativistic astrophysical outflows. In order for a flow to be accelerated to high Lorentz factors the internal energy per baryon at the flow injection point must largely exceed unity. This internal energy may have a thermal origin as, e.g., in hydrodynamical fireball models, or a magnetic origin, as in pulsar winds and outflows from rotating black holes. A basic question in the former case is how to avoid excessive mass loading. A key issue in the latter case is the conversion of magnetic energy to kinetic energy. Observations seem to indicate that collimation is a generic feature of astrophysical outflows, suggesting that confinement by the ambient medium may play an important role in the dynamics of the system. In the following only steady flows will be considered, for which simple analytic solutions can be obtained.
Let us consider first an unmagnetized spherical wind. In general, the wind may consist of a mixture of baryons, radiation and electron–positron plasma, which in sufficiently compact regions can be taken to be in local equilibrium. The flow is then characterized by the proper baryon density nb, pressure p, temperature T and velocity uμ = (γ, γv). We further assume that the flow is adiabatic and not subject to any external forces, including gravity (the effect of gravity will be considered in the following sections).
In this decade, the transient universe will be mapped out in great detail by the emerging wide-field multiwavelength surveys, and neutrino and gravitational-wave detectors, promising to probe the astronomical and physical origin of the most extreme relativistic sources. This volume introduces the physical processes relevant to the source modeling of the transient universe. Ideal for graduate students and researchers in astrophysics, this book gives a unified treatment of relativistic flows associated with compact objects, their dissipation and emission in electromagnetic, hadronic and gravitational radiation. After introducing the source classes, the authors set out various mechanisms for creating magnetohydodynamic outflows in winds, jets and blast waves and their radiation properties. They then go on to discuss properties of accretion flows around rotating black holes and their gravitational wave emission from wave instabilites with implications for the emerging gravitational wave experiments. Graduate students and researchers can gain an understanding of data analysis for gravitational-wave data.
The extent of your consciousness is limited only by your ability to love and to embrace with your love the space around you, and all it contains.
Napoleon Bonaparte (1769–1821)
Astrophysical flows as discussed in the previous chapter are subject to steepening, especially when coming off a time-dependent or intermittent source. Steepening results in shocks, where energy in bulk motion is partially dissipated into heat. Strong shocks thereby produce radiation, as alluded to in the general scheme pointed out in Section 1.2, further accompanied by entropy creation. In this chapter, we elucidate the physical processes governing various types of shocks.
Nonlinear steepening of relativistic disturbances
The analysis of small-amplitude MHD waves outlined in Section 5.3 indicates that the speed at which a linear disturbance propagates, Eq. (5.43), depends on local conditions. It is naively expected that over sufficiently long times the wave will be distorted, as the phase speed itself changes over the course of the wave trajectory. Waves generated at some location will eventually steepen into shocks, at which point the fluid picture breaks down. Inside the shock transition the wave dissipates, converting bulk energy into heat. The transition occurs over kinetic scales, roughly the collision length in collisional shocks, the skin depth in collisionless shocks, and the Thomson mean free path in radiation mediated shocks.
Riemann invariants and characteristics
A convenient way to analyze wave steepening is to write the MHD equations in terms of the so-called Riemann invariants, developed in compressible fluid dynamics to understand the process of steepening and shock formation.
There are two possible outcomes: if the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery.
Enrico Fermi (1901–1954)
The ejection of supersonic outflows drives the formation of strong shocks that propagate into the surrounding medium. Examples are blast waves that form in stellar and galactic explosions. The supernovae accompanying the death of a star, the afterglow emission that follows a GRB explosion, and the radio lobes observed in radio galaxies and blazars are clear signatures of those blast waves. When the energy released by the source is large such that E > (Mj + ρiV)c2, where Mj is the mass of the ejecta, ρi the ambient density and V the volume swept by the shock, the blast wave motion is relativistic. The most notable example is the afterglowshell in GRBs.
The structure formed in spherical explosions at early times is shown schematically in Fig. 8.1. It consists of a forward shock that propagates in the ambient medium, a reverse shock crossing the ejecta, and a contact discontinuity separating the shocked ejecta and the shocked ambient medium. This structure is clearly seen in the X-ray image of the SNR DEM L71 in Fig. 8.2. The early phases in the evolution of a blast wave are considered in detail in Section 8.6.
At sufficiently late times a major fraction of the explosion energy is contained in the shell of shocked ambient medium and the effect of the ejecta on the evolution of the forward shock can be ignored. This stage is well described by the impulsive blast wave model discussed in Section 8.2.
And these little things may not seem like much but after a while they take you off on a direction where you may be a long way off from what other people have been thinking about.
Roger Penrose (1931–)
General relativity gives a complete description of gravitation as it follows from conservation of energy–momentum, general gauge covariance and causality. While it has unprecedented predictive power towards cosmology, gravitational collapse and gravitational waves, only recently has gravitation become an experimental science beyond Newton's law of attraction  and beyond gravitational redshift , with the advance of LAGEOS, LAGEOS II  and Gravity Probe B . These controlled experiments provide the first direct measurements of geodetic and frame-dragging precessions combined, from which we can gain confidence in astrophysical models involving strong gravitational fields and their radiation processes.
In this chapter, we summarize the most immediate aspects in a geometrical way to facilitate applications to astrophysics. We follow the general idea that the essential properties of general relativity derive from the Riemann tensor [485, 141]. We use the tensor notation of  with Latin indices and use geometrical units in which Newton's constant and the velocity of light are set equal to 1 unless otherwise specified.
General relativity describes the motion of particles in terms of world-lines xb(τ) in a curved spacetime with coordinates xb, with the eigentime τ commonly used as the parameter of the world-line family.