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We describe here efforts to create and study magnetized electron–positron pair plasmas, the existence of which in astrophysical environments is well-established. Laboratory incarnations of such systems are becoming ever more possible due to novel approaches and techniques in plasma, beam and laser physics. Traditional magnetized plasmas studied to date, both in nature and in the laboratory, exhibit a host of different wave types, many of which are generically unstable and evolve into turbulence or violent instabilities. This complexity and the instability of these waves stem to a large degree from the difference in mass between the positively and the negatively charged species: the ions and the electrons. The mass symmetry of pair plasmas, on the other hand, results in unique behaviour, a topic that has been intensively studied theoretically and numerically for decades, but experimental studies are still in the early stages of development. A levitated dipole device is now under construction to study magnetized low-energy, short-Debye-length electron–positron plasmas; this experiment, as well as a stellarator device that is in the planning stage, will be fuelled by a reactor-based positron source and make use of state-of-the-art positron cooling and storage techniques. Relativistic pair plasmas with very different parameters will be created using pair production resulting from intense laser–matter interactions and will be confined in a high-field mirror configuration. We highlight the differences between and similarities among these approaches, and discuss the unique physics insights that can be gained by these studies.
To compare diet quality and its association with excess body weight (EBW: overweight/obesity), central adiposity (CA) and CVD risk factors (CVDR) among adolescents from Brazil and USA.
Design:
Data from two cross-sectional surveys: Health Survey of São Paulo (ISA-Nutrition) and Hispanic Community Health Study/Study of Latino Youth (SOL-Youth). Dietary intake was assessed from 24-h recalls, and diet quality using the Alternate Healthy Eating Index-2010 (AHEI) developed in the USA and the Revised Brazilian Healthy Eating Index (BHEI-R). CVDR was defined as ≥3 of: obesity, elevated blood pressure, dyslipidaemia, high plasma glucose and insulin resistance. Adjusted OR for EBW, CA and CVDR by diet quality were tested using logistic regression.
Setting:
São Paulo, Brazil; and Chicago, IL; Miami, FL; Bronx, NY; San Diego, CA.
Participants:
Adolescents (12–16 years) living in São Paulo (n 189) and USA (n 787).
Results:
ISA-Nutrition individuals with EBW (v. without) had marginally lower (unhealthier) scores for whole grains using BHEI-R and sugary beverages using AHEI. SOL-Youth individuals with EBW had lower scores of nuts/legumes using AHEI, and Na using BHEI-R, but higher scores of whole grains and dairy using BHEI-R. In ISA-Nutrition, BHEI-R was inversely associated with EBW (OR = 0·87; 95 % CI 0·80, 0·95) and CVDR (OR = 0·89; 95 % CI 0·80, 0·98). In SOL-Youth, AHEI was inversely associated with EBW (OR = 0·93; 95 % CI 0·87, 0·99).
Conclusions:
Dietary improvements should be made by adolescents in both USA and Brazil. Healthier diet quality as measured with the country-specific index was associated with lower odds of EBW in Brazilian and USA-Hispanic/Latino adolescents, and with lower CVDR in Brazilian adolescents.
To elucidate mechanisms across family function, home environment and eating behaviours within sociocultural context among Hispanic youth.
Design:
Two models tested via path analysis (youth fruit and vegetable (FV) consumption; empty energy consumption) using data from the Study of Latino Youth (2011–2013).
Setting:
Chicago, IL; Miami, FL; Bronx, NY; San Diego, CA.
Participants:
Youth (8–16-year-olds), n 1466.
Results:
Youth ate 2·4 servings of FV per d and received 27 % of total energy from empty energies. Perceiving higher acculturative stress was indirectly associated with lower FV consumption via a pathway of low family function and family support for FV (β = −0·013, P < 0·001) and via lower family closeness and family support (β = −0·004, P = 0·004). Being >12-year-olds was indirectly associated with lower FV consumption via lower family closeness and family support (β = −0·006, P < 0·001). Household food security was indirectly associated with greater FV consumption via family closeness and family support (β = 0·005, P = 0·003). In contrast, perceiving higher acculturative stress was indirectly associated with higher empty energy consumption (via family closeness and family support: β = 0·003, P = 0·028 and via low family function and low family support: β = 0·008, P = 0·05). Being older was associated with higher consumption of empty energies via family closeness (related to family support: β = 0·04, P = 0·016; parenting strategies for eating: β = 0·002, P = 0·049).
Conclusions:
Findings suggest pathways of influence across demographic and sociocultural context, family dynamics and home environment. The directionality of these associations needs confirmation using longitudinal data.
We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain (
${\sim}2.8\,\mbox{K Jy}^{-1}$
) low-system temperature (
${\sim}18\,\mbox{K at }20\,\mbox{cm}$
) radio array that currently operates at 580–1 670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar
$\mbox{J}0737{-}3039\mbox{A}$
, pulse profiles from 34 millisecond pulsars (MSPs) from a single 2.5-h observation of the Globular cluster Terzan 5, the rotation measure of Ter5O, a 420-sigma giant pulse from the Large Magellanic Cloud pulsar PSR
$\mbox{J}0540{-}6919$
, and nulling identified in the slow pulsar PSR J0633–2015. One of the key design specifications for MeerKAT was absolute timing errors of less than 5 ns using their novel precise time system. Our timing of two bright MSPs confirm that MeerKAT delivers exceptional timing. PSR
$\mbox{J}2241{-}5236$
exhibits a jitter limit of
$<4\,\mbox{ns h}^{-1}$
whilst timing of PSR
$\mbox{J}1909{-}3744$
over almost 11 months yields an rms residual of 66 ns with only 4 min integrations. Our results confirm that the MeerKAT is an exceptional pulsar telescope. The array can be split into four separate sub-arrays to time over 1 000 pulsars per day and the future deployment of S-band (1 750–3 500 MHz) receivers will further enhance its capabilities.
Acid sphingomyelinase (A-SMase) is a glycoprotein that functions as a lysosomal hydrolase, catalysing the degradation of sphyngomyelin to phosphorylcholine and ceramide. Several lines of evidence suggest its central role in all three types of apoptosis. The activation of neuronal A-SMase has been shown to be important in the stress-induced apoptotic death of hippocampal neurons. The aim of the present study was to investigate the association between the activity of A-SMase, hippocampal volume and memories function in healthy young volunteers.
Materials and Methods:
The activity of A-SMase was measured in peripheral blood mononuclear cells of 19 healthy female students of the University of Erlangen- Nuernberg (26,32 ± 3,95 years old, Body mass: 22,29 ± 2,63 kgr/m2). The hippocampal formation was outlined in high-resolution anatomical magnetic resonance imaging data. The memory function was assessed with the Inventory for Memory diagnostics (Inventar zur Gedaechtnisdiagnostik). Correlations between continuous variables were examined, using Spearman's rank correlation coefficient.
Results:
The activity of A-SMase did not correlate with hippocampal volume and memory performance.
Conclusions:
These findings indicate that the activity of the A-SMase influences neither the brain hippocampal volume of young healthy females, nor their memory performance.
Successful conservation depends on human attitudes, values, and support. Increasingly scientists and managers analyse not only species status and needs, but also the long-term cost, risk, and effectiveness of activities. Socioeconomic costs and benefits are integral to these analyses. Gorongosa National Park in Mozambique provides a case study of conservation integrated with local community needs. Endangered Delta smelt in California exemplify conflicts around water apportionment. Case studies demonstrating the importance of socioeconomic considerations are provided by management of gray wolves and grizzly bears in the United States. The story of sage grouse illustrates how a regional agreement that resulted from many years of collaboration among stakeholders can be nullified by political changes at the national level. The cultural and socioeconomic values and rights of indigenous people play a prominent role in salmon management that can run counter to the interests of hydroelectric companies and other water users. Case studies illustrate how habitat management can be facilitated by participation by non-governmental organizations. Socioeconomic and political consideration also underlie the question of who can take responsibility for managing conservation-reliant species.
A conservation-reliant species is vulnerable to threats that persist; it requires continued management intervention to prevent a decline toward extinction or to maintain a population. The degree of conservation reliance varies over time and among species. Globally, the extent of conservation reliance is accelerating faster than we can provide resources to combat extinctions and promote recovery. A species is recognized as being conservation reliant or emerging from that status based on a general assessment that includes status and threats, the potential for managing the threats, actions taken to manage the threats and the species itself, population monitoring, and monitoring of threats. Species differ in their susceptibility to threats and their potential to respond to management actions, and threats differ in manageability. We use California condor management as a case study for these features of conservation reliance.
Understanding threats and our ability to manage them is the first step in shepherding conservation-reliant species toward sustainability or recovery. This chapter contrasts situations in which a single threat dominates with more complex situations in which multiple threats interact. Interactions among threats raise the likelihood of conservation reliance, as this chapter illustrates in a case study of vultures. Several other case studies illustrate the effectiveness of different legal and management approaches to imperilment and the importance of identifying its root causes. Case studies, including some revolving around dams, also illustrate the complexities that attend socioeconomic drivers of imperilment and differences in the scale and manageability of threats. The chapter also describes several threats such as storms, tsunamis, or volcanic eruptions that are not manageable.
The array of tools for addressing the needs of imperiled and conservation-reliant species is increasing. This chapter provides case studies and examples of the use of translocation and captive breeding for addressing threats, and discuss attributes of receiving sites. Tools for tracking species movements and for remote sensing can efficiently provide large amounts of habitat and species data. Sometimes tools can be used to address common threats such as those created by habitat change or pesticide use, benefitting multiple species. We provide Old World vultures offer a case study. Managing for surrogate, umbrella, indicator, focal, keystone, or pollinator species may assist other species as well. Such roles should be acknowledged in prioritizing conservation activities. Emerging technologies, including genetic tools and artificial intelligence, can help to address imperilment and conservation reliance if ethical issues can be navigated.
Many nations have developed policies and enforced legal approaches for addressing the needs of species at risk of extinction. Generally, however, conservation reliance is not acknowledged legally and is therefore ignored. Increasingly, legal approaches reflect the importance of (1) values in addition to hunting and fishing, (2) wildlife as a shared resource, (3) intrinsic rather than instrumental value, (4) helping species to become self-sustaining, and (5) long-term support for imperiled species. The International Union for the Conservation of Naturehas provided an international standard for recognizing species status. In the United States, the Endangered Species Act and National Environmental Policy Act provide a legal framework for species conservation that has been effective (although these acts have also spawned many legal challenges that have consumed the time and resources of stakeholders). The effectiveness of imperiled species laws depends on funding that can vary, leading to varying implementation and enforcement. Conservation reliance is seldom addressed explicitly. Responsibility for implementation may be spread across national, state or province, and more local entities.
Current methods for making decisions about what to fund and at what level are not sufficiently transparent or objective. Acknowledging conservation reliance fosters a realistic approach and outcomes. Prioritization requires an agreed-upon pool of species to consider within a defined area. Defining and ranking prioritization criteria presents a variety of challenges, including accounting for the manageability of threats, species vulnerability, and species genetic and phenotypic traits. Including social and economic factors increases the probability that plans will be implemented. This chapter also considers how factor weightings are derived and means of dealing with uncertainty. Four examples of prioritization processes illustrate the variety of current approaches. Few approaches explicitly consider the long-term demands of conservation reliance. The ethics that underlie conservation triage affect how people undertake prioritization. This book advocates the use of explicit prioritization criteria that include uncertainties and derive from values and interests of diverse stakeholders. Models should acknowledge a wide array of ecological and socioeconomic costs and benefits, probabilities of success, and projected conservation reliance.
Conservation reliance exists along a spectrum from species extinction to species recovery; from requiring intensive to minimal management. This chapter provides case studies of full or partial recovery and explores what made this possible using the Oregon chub, Aleutian cackling goose, southern white rhinoceros, black-capped vireo, and Robbins’ cinquefoil. Toward the other end of the spectrum, continued translocations or releases are required to maintain Oregon silverspot butterflies and Chatham Island black robins. Management is not always successful, however, as seen for Australian woylies. Some species, such as the Guam kingfisher, are extinct in the wild but maintained in zoos. Finally, there are lessons to be learned from species such as the po’ouli, dusky seaside sparrow, and Christmas Island pipistrelle, for which investments were too little or too late. Management of imperiled species is a societal investment and people’s attitudes play an important role in successful recovery. Participation by citizens and non-governmental organizations is particularly important when species are conservation reliant, as the long-term investment required can rarely be sustained otherwise.
People differ in how and how much they value nature, and in their attitudes toward conservation. This affects the implementation of laws and regulations and the criteria used in prioritization of conservation actions. Yet collaboration is essential, especially when conservation reliance requires long-term commitments. Individuals, communities, government agencies, and non-governmental organizations must all be involved. Shepherding nature is about taking responsibility for watching over and caring for species and Earth’s biodiversity. Countering the rising rate of extinctions will require a transformative change in how people relate to the environment, nature, and one another.
Expanding the scope of conservation beyond species and taking a broader, more holistic approach can provide greater and more lasting benefits to a wider ecological community. However, doing so can reduce our capacity to understand and ameliorate threats to individual species. Factors that favor a broader approach can be used to prioritize areas for protection. Protected areas can benefit from appropriate management of surrounding areas and from connectivity to other protected or partially protected habitat. Eradicating invasive species can benefit multiple imperiled species—although fencing and monitoring entail long-term costs, contributing to conservation reliance. This chapter provides examples, especially from oceanic islands. Managing fire regimes, either by controlling or setting fires, is another way to improve habitat and benefit multiple species. There are trade-offs in both cost and effectiveness between single- and multi-species management.