Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockstrom and colleagues.

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A safe operating space for humanity

The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system. Here, we revise and update the planetary boundary framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundaries—climate change and biosphere integrity—have been identified, each of which has the potential on its own to drive the Earth system into a new state should they be substantially and persistently transgressed.

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Planetary boundaries: Guiding human development on a changing planet

Global energy consumption is projected to increase, even in the face of substantial declines in energy intensity, at least 2-fold by midcentury relative to the present because of population and economic growth. This demand could be met, in principle, from fossil energy resources, particularly coal. However, the cumulative nature of CO2 emissions in the atmosphere demands that holding atmospheric CO2 levels to even twice their preanthropogenic values by midcentury will require invention, development, and deployment of schemes for carbon-neutral energy production on a scale commensurate with, or larger than, the entire present-day energy supply from all sources combined. Among renewable energy resources, solar energy is by far the largest exploitable resource, providing more energy in 1 hour to the earth than all of the energy consumed by humans in an entire year. In view of the intermittency of insolation, if solar energy is to be a major primary energy source, it must be stored and dispatched on demand to the end user. An especially attractive approach is to store solar-converted energy in the form of chemical bonds, i.e., in a photosynthetic process at a year-round average efficiency significantly higher than current plants or algae, to reduce land-area requirements. Scientific challenges involved with this process include schemes to capture and convert solar energy and then store the energy in the form of chemical bonds, producing oxygen from water and a reduced fuel such as hydrogen, methane, methanol, or other hydrocarbon species.

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Powering the planet: Chemical challenges in solar energy utilization

The recent completion of drilling at Vostok station in East Antarctica has allowed the extension of the ice record of atmospheric composition and climate to the past four glacial–interglacial cycles. The succession of changes through each climate cycle and termination was similar, and atmospheric and climate properties oscillated between stable bounds. Interglacial periods differed in temporal evolution and duration. Atmospheric concentrations of carbon dioxide and methane correlate well with Antarctic air-temperature throughout the record. Present-day atmospheric burdens of these two important greenhouse gases seem to have been unprecedented during the past 420,000 years.

Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica

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The immune modulator FTY720 targets sphingosine 1-phosphate receptors.

The invention provides novel pteridine nucleotide which are highly fluorescent under physiological conditions and which may be used in the chemical synthesis of fluorescent oligonucleotides. The invention further provides for fluorescent oligonucleotides comprising one or more pteridine nucleotides. In addition the invention provides for pteridine nucleotide triphosphates which may be used as the constituent monomers in DNA amplification procedures.

Pteridine nucleotide analogs as fluorescent dna probes

OBJECTIVE. The growing shift toward home care services assumes that “being home is good” and that this is the most desirable option. Although ethical issues in medical decision-making have been examined in numerous contexts, home care decisions for technology-dependent children and the moral dilemmas that this population confronts remain virtually unknown. This study explored the moral dimension of family experience through detailed accounts of life with a child who requires assisted ventilation at home. This study involved an examination of moral phenomena inherent in (1) the individual experiences of the ventilator-assisted child, siblings, and parents and (2) everyday family life as a whole. METHODS. A qualitative method based on Richard Zaner9s interpretive framework was selected for this study. The population of interest for this study was the families of children who are supported by a ventilator or a positive-pressure device at home. Twelve families (38 family members) were recruited through the Quebec Program for Home Ventilatory Assistance. Children in the study population fell into 4 diagnostic groups: (1) abnormal ventilatory control (eg, central hypoventilation syndrome), (2) neuromuscular disorders, (3) spina bifida, and (4) craniofacial or airway abnormalities resulting in upper airway obstruction. All 4 of these diagnostic groups were included in this study. Among the 12 children recruited, 4 received ventilation via tracheostomies, and 8 received ventilation with face masks. All of the latter received ventilation only at night, except for 1 child, who received ventilation 24 hours a day. Family moral experiences were investigated using semistructured interviews and fieldwork observations conducted in the families9 homes. RESULTS. Data analysis identified 6 principal themes. The themes raised by families whose children received ventilation invasively via a tracheostomy were not systematically different or more distressed than were families of children with face masks. The principal themes were (1) confronting parental responsibility: parental responsibility was described as stressful and sometimes overwhelming. Parents needed to devote extraordinary care and attention to their children9s needs. They struggled with the significant emotional strain, physical and psychological dependence of the child, impact on family relationships, living with the daily threat of death, and feeling that there was “no free choice” in the matter: they could not have chosen to let their child die. (2) Seeking normality: all of the families devoted significant efforts toward normalizing their experiences. They created common routines so that their lives could resemble those of “normal” families. These efforts seemed motivated by a fundamental striving for a stable family and home life. This “striving for stability” was sometimes undermined by limitations in family finances, family cohesion, and unpredictability of the child9s condition. (3) Conflicting social values: families were offended by the reactions that they faced in their everyday community. They believe that the child9s life is devalued, frequently referred to as a life not worth maintaining. They felt like strangers in their own communities, sometimes needing to seclude themselves within their homes. (4) Living in isolation: families reported a deep sense of isolation. In light of the complex medical needs of these children, neither the extended families nor the medical system could support the families9 respite needs. (5) What about the voice of the child? The children in this study (patients and siblings) were generally silent when asked to talk about their experience. Some children described their ventilators as good things. They helped them breathe and feel better. Some siblings expressed resentment toward the increased attention that their ventilated sibling was receiving. (6) Questioning the moral order: most families questioned the “moral order” of their lives. They contemplated how “good things” and “bad things” are determined in their world. Parents described their life as a very unfair situation, yet there was nothing that they could do about it. Finally, an overarching phenomenon that best characterizes these families9 experiences was identified: daily living with distress and enrichment. Virtually every aspect of the lives of these families was highly complicated and frequently overwhelming. An immediate interpretation of these findings is that families should be fully informed of the demands and hardships that would await them, encouraging parents perhaps to decide otherwise. This would be but a partial reading of the findings, because despite the enormous difficulties described by these families, they also reported deep enrichments and rewarding experiences that they could not imagine living without. Life with a child who requires assisted ventilation at home involves living every day with a complex tension between the distresses and enrichments that arise out of this experience. The conundrum inherent in this situation is that there are no simple means for reconciling this tension. This irreconcilability is particularly stressful for these families. Having their child permanently institutionalized or “disconnected” from ventilation (and life) would eliminate both the distresses and the enrichments. These options are outside the realm of what these families could live with, aside from the 1 family whose child is now permanently hospitalized, at a tremendous cost of guilt to the family. CONCLUSIONS. These findings make important contributions by (1) advancing our understanding of the moral experiences of this group of families; (2) speaking to the larger context of other technology-dependent children who require home care; (3) relating home care experiences to neonatal, critical care, and other hospital services, suggesting that these settings examine their approaches to this population that may impose preventable burdens on the lives of these children and their families; and (4) examining a moral problem with an empirical method. Such problems are typically investigated through conceptual analyses, without directly examining lived experience. These findings advance our thinking about how we ought to care for these children, through a better understanding of what it is like to care for them and the corresponding major distresses and rewarding enrichments. These findings call for an increased sensitization to the needs of this population among staff in critical care, acute, and community settings. Integrated community support services are required to help counter the significant distress endured by these families. Additional research is required to examine the experience of other families who have decided either not to bring home their child who requires ventilation or withdraw ventilation and let the child die.

https://pediatrics.aappublications.org/content/pediatrics/117/1/e48.full.pdf

Michael Davis

Papers

Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica

The immune modulator FTY720 targets sphingosine 1-phosphate receptors.

Pteridine nucleotide analogs as fluorescent dna probes

Daily living with distress and enrichment: the moral experience of families with ventilator-assisted children at home.

Sphingosine 1-phosphate analogs as receptor antagonists.