First-ever seizure and eligibility for commercial motor vehicle driving.

BACKGROUND: After a first-ever seizure, 6 months of seizure freedom is usually required before returning to driving a private motor vehicle, after which the annual risk of seizure recurrence has fallen to ≤20%. Stricter criteria apply for commercial driver's licence (CDL) holders, and a longer period of seizure freedom sufficient for the annual risk of recurrence to be <2% is recommended. However, CDL guidelines are based on little data with few studies having long-term follow-up. METHODS: 1714 patients with first-ever seizures were prospectively studied. Seizure recurrence was evaluated using survival analysis. The annual conditional risk of seizure recurrence was calculated for patients with first-ever unprovoked and acute symptomatic seizures, and according to the presence or absence of clinical, electroencephalogram (EEG) and neuroimaging risk factors for recurrence. RESULTS: The annual risk of recurrence for unprovoked first seizures did not fall below 2% until after 9 years of seizure freedom. The annual risk after 5 years of seizure freedom was still 3.9% (95% CI 1.8% to 6.1%) including for those without epileptiform abnormalities on EEG and with normal imaging. For acute symptomatic first seizures, the annual recurrence risk was 4.5% (95% CI 2.3% to 6.7%) after 1 year and fell below 2% only after 4 years of seizure freedom. CONCLUSIONS: For unprovoked and acute symptomatic first-ever seizure and CDL, a higher-than-expected annual seizure risk persists beyond the currently recommended seizure-free periods, even in those without risk factors for recurrence. Our data can inform decisions regarding a return to driving for CDL holders after first-ever seizure.

Long-term physical and psychiatric morbidities and mortality of untreated, deferred, and immediately treated epilepsy.

OBJECTIVE: In Australia, 30% of newly diagnosed epilepsy patients were not immediately treated at diagnosis. We explored health outcomes between patients receiving immediate, deferred, or no treatment, and compared them to the general population. METHODS: Adults with newly diagnosed epilepsy in Western Australia between 1999 and 2016 were linked with statewide health care data collections. Health care utilization, comorbidity, and mortality at up to 10 years postdiagnosis were compared between patients receiving immediate, deferred, and no treatment, as well as with age- and sex-matched population controls. RESULTS: Of 603 epilepsy patients (61% male, median age = 40 years) were included, 422 (70%) were treated immediately at diagnosis, 110 (18%) received deferred treatment, and 71 (12%) were untreated at the end of follow-up (median = 6.8 years). Immediately treated patients had a higher 10-year rate of all-cause admissions or emergency department presentations than the untreated (incidence rate ratio [IRR] = 2.0, 95% confidence interval [CI] = 1.4-2.9) and deferred treatment groups (IRR = 1.7, 95% CI = 1.0-2.8). They had similar 10-year risks of mortality and developing new physical and psychiatric comorbidities compared with the deferred and untreated groups. Compared to population controls, epilepsy patients had higher 10-year mortality (hazard ratio = 2.6, 95% CI = 2.1-3.3), hospital admissions (IRR = 2.3, 95% CI = 1.6-3.3), and psychiatric outpatient visits (IRR = 3.2, 95% CI = 1.6-6.3). Patients with epilepsy were also 2.5 (95% CI = 2.1-3.1) and 3.9 (95% CI = 2.6-5.8) times more likely to develop a new physical and psychiatric comorbidity, respectively. SIGNIFICANCE: Newly diagnosed epilepsy patients with deferred or no treatment did not have worse outcomes than those immediately treated. Instead, immediately treated patients had greater health care utilization, likely reflecting more severe underlying epilepsy etiology. Our findings emphasize the importance of individualizing epilepsy treatment and recognition and management of the significant comorbidities, particularly psychiatric, that ensue following a diagnosis of epilepsy.

Adult-onset Kufs disease.

A young man from Pakistan had his first-ever tonic-clonic seizure while playing cricket. Since age 12 years, he had reported involuntary jerks and tremulousness, sometimes with falls, particularly with bright lights. Family history included a brother who developed seizures with myoclonus in his mid-20s and parental consanguinity. Developmental history was normal. Examination identified cognitive impairment with action myoclonus. His clinical presentation raised suspicion of a progressive myoclonus epilepsy. MR scan of the brain showed white matter changes suggesting leucodystrophy with cortical atrophy. Electroencephalogram showed generalised epileptiform abnormalities with photoparoxysmal responses, including at low frequencies (1 Hz). Cortical hyperexcitability was confirmed with giant median somatosensory evoked potentials and long loop reflexes at rest. Multichannel electromyography showed action myoclonus with variable synchronous and asynchronous agonist and antagonist muscle activation with short-burst duration of 25-75 ms, and jerk-locked back-averaging showed premyoclonic potentials consistent with cortical myoclonus. Genetic sequencing identified a homozygous missense variant in the CLN6 gene (c.768C>G p.(Asp256Glu), confirming Kufs disease type A.

Coral adaptive capacity insufficient to halt global transition of coral reefs into net erosion under climate change.

Projecting the effects of climate change on net reef calcium carbonate production is critical to understanding the future impacts on ecosystem function, but prior estimates have not included corals' natural adaptive capacity to such change. Here we estimate how the ability of symbionts to evolve tolerance to heat stress, or for coral hosts to shuffle to favourable symbionts, and their combination, may influence responses to the combined impacts of ocean warming and acidification under three representative concentration pathway (RCP) emissions scenarios (RCP2.6, RCP4.5 and RCP8.5). We show that symbiont evolution and shuffling, both individually and when combined, favours persistent positive net reef calcium carbonate production. However, our projections of future net calcium carbonate production (NCCP) under climate change vary both spatially and by RCP. For example, 19%-35% of modelled coral reefs are still projected to have net positive NCCP by 2050 if symbionts can evolve increased thermal tolerance, depending on the RCP. Without symbiont adaptive capacity, the number of coral reefs with positive NCCP drops to 9%-13% by 2050. Accounting for both symbiont evolution and shuffling, we project median positive NCPP of coral reefs will still occur under low greenhouse emissions (RCP2.6) in the Indian Ocean, and even under moderate emissions (RCP4.5) in the Pacific Ocean. However, adaptive capacity will be insufficient to halt the transition of coral reefs globally into erosion by 2050 under severe emissions scenarios (RCP8.5).

First seizure from sleep: Clinical features and prognosis.

OBJECTIVES: Patients with a first-ever unprovoked seizure commonly have subsequent seizures and identifying predictors of recurrence has important management implications. Both prior brain insult and epileptiform abnormalities on electroencephalography (EEG) are established predictors of seizure recurrence. Some studies suggest that a first-ever seizure from sleep has a higher likelihood of recurrence. However, with relatively small numbers and inconsistent definitions, more data are required. METHODS: Prospective cohort study of adults with first-ever unprovoked seizure seen by a hospital-based first seizure service between 2000 and 2015. Clinical features and outcomes of first-ever seizure from sleep and while awake were compared. RESULTS: First-ever unprovoked seizure occurred during sleep in 298 of 1312 patients (23%), in whom the 1-year cumulative risk of recurrence was 56.9% (95% confidence interval [CI] 51.3-62.6) compared to 44.2% (95% CI 41.1-47.3, p < .0001) for patients with first-ever seizure while awake. First-ever seizure from sleep was an independent predictor of seizure recurrence, with a hazard ratio [HR] of 1.44 (95% CI 1.23-1.69), similar to epileptiform abnormalities on EEG (HR 1.48, 95% CI 1.24-1.76) and remote symptomatic etiology (HR 1.47, 95% CI 1.27-1.71). HR for recurrence in patients without either epileptiform abnormalities or remote symptomatic etiology was 1.97 (95% CI 1.60-2.44) for a sleep seizure compared to an awake seizure. For first seizure from sleep, 76% of second seizures also arose from sleep (p < .0001), with 65% of third seizures (p < .0001) also from sleep. Seizures from sleep were less likely to be associated with injury other than orolingual trauma, both with the presenting seizure (9.4% vs 30.6%, p < .0001) and first recurrence (7.5% vs 16.3%, p = .001). SIGNIFICANCE: First-ever unprovoked seizures from sleep are more likely to recur, independent of other risk factors, with recurrences also usually from sleep, and with a lower risk of seizure-related injury. These findings may inform treatment decisions and counseling after first-ever seizure.

Mortality after a first-ever unprovoked seizure.

OBJECTIVE: Although increased mortality associated with epilepsy is well understood, data in patients after their first-ever seizure are limited. We aimed to assess mortality after a first-ever unprovoked seizure and identify causes of death (CODs) and risk factors. METHODS: A prospective cohort study was undertaken of patients with first-ever unprovoked seizure between 1999 and 2015 in Western Australia. Two age-, gender-, and calendar year-matched local controls were obtained for each patient. Mortality data, including COD, based on International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes, were obtained. Final analysis was performed in January 2022. RESULTS: One thousand two hundred seventy-eight patients with a first-ever unprovoked seizure were compared to 2556 controls. Mean follow-up was 7.3 years (range = .1-20). Overall hazard ratio (HR) for death after a first unprovoked seizure compared to controls was 3.06 (95% confidence interval [CI] = 2.48-3.79), with HRs of 3.30 (95% CI = 2.26-4.82) for those without seizure recurrence and 3.21 (95% CI = 2.47-4.16) after a second seizure. Mortality was also increased in patients with normal imaging and no identified cause (HR = 2.50, 95% CI = 1.82-3.42). Multivariate predictors of mortality were increasing age, remote symptomatic causes, first seizure presentation with seizure cluster or status epilepticus, neurological disability, and antidepressant use at time of first seizure. Seizure recurrence did not influence mortality rate. The commonest CODs were neurological, most relating to the underlying cause of seizures rather than being seizure-related. Substance overdoses and suicide were more frequent CODs in patients compared to controls and were commoner than seizure-related deaths. SIGNIFICANCE: Mortality is increased two- to threefold after a first-ever unprovoked seizure, independent of seizure recurrence, and is not only attributable to the underlying neurological etiology. The greater likelihood of deaths related to substance overdose and suicide highlights the importance of assessing psychiatric comorbidity and substance use in patients with first-ever unprovoked seizure.

Microbial evolutionary strategies in a dynamic ocean.

Marine microbes form the base of ocean food webs and drive ocean biogeochemical cycling. Yet little is known about the ability of microbial populations to adapt as they are advected through changing conditions. Here, we investigated the interplay between physical and biological timescales using a model of adaptation and an eddy-resolving ocean circulation climate model. Two criteria were identified that relate the timing and nature of adaptation to the ratio of physical to biological timescales. Genetic adaptation was impeded in highly variable regimes by nongenetic modifications but was promoted in more stable environments. An evolutionary trade-off emerged where greater short-term nongenetic transgenerational effects (low-γ strategy) enabled rapid responses to environmental fluctuations but delayed genetic adaptation, while fewer short-term transgenerational effects (high-γ strategy) allowed faster genetic adaptation but inhibited short-term responses. Our results demonstrate that the selective pressures for organisms within a single water mass vary based on differences in generation timescales resulting in different evolutionary strategies being favored. Organisms that experience more variable environments should favor a low-γ strategy. Furthermore, faster cell division rates should be a key factor in genetic adaptation in a changing ocean. Understanding and quantifying the relationship between evolutionary and physical timescales is critical for robust predictions of future microbial dynamics.

Risk factors and consequences of self-discontinuation of treatment by patients with newly diagnosed epilepsy.

OBJECTIVE: Patients with epilepsy not uncommonly self-discontinue treatment with antiseizure medications (ASM). The rate, reasons for this, and consequences have not been well studied. METHODS: We analyzed self-discontinuation of ASM treatment in patients with recently diagnosed epilepsy via review of clinic letters and hospital correspondence in a prospective cohort of first seizure patients. RESULTS: We studied 489 patients with newly diagnosed and treated epilepsy (median age 41, range 14-88, 62% male), followed up for a median duration of 3.0 years (interquartile range [IQR]: 1.2-6.0). Seventy eight (16.0%) self-discontinued ASM therapy after a median treatment duration of 1.4 years (IQR: 0.4-2.9), and after a median duration of seizure freedom of 11.8 months (IQR: 4.6-31.8). Patients commonly self-discontinued treatment due to adverse effects (41%), perception that treatment was no longer required (35%), and planned or current pregnancy (12%). Patients who self-discontinued were less likely to have epileptogenic lesions on neuroimaging (hazard ratio [HR] = 0.44, 95% confidence interval [CI]: 0.23-0.83), presentation with seizure clusters (HR = 0.32, 95% CI: 0.14-0.69) and presentation with tonic-clonic seizures (HR = 0.36, 95% CI: 0.19-0.70). Patients with shorter interval since the last seizure (HR = 0.76, 95% CI: 0.66-0.86) were more likely to self-discontinue treatment. Sleep deprivation prior to seizures before diagnosis (HR = 1.80, 95% CI: 1.05-3.09) and significant alcohol or illicit drug use (HR = 2.35, 95% CI: 1.20-4.59) were also associated with higher rates of discontinuation. After discontinuation, 51 patients (65%) experienced seizure recurrence, and 43 (84%) restarted treatment. Twenty two patients (28%) experienced a seizure-related injury after treatment discontinuation. SIGNIFICANCE: Self-initiated discontinuation of ASM treatment was not uncommon in patients with newly treated epilepsy. Reasons for discontinuation highlight areas for improved discussion with patients, including the chronicity of epilepsy and management strategies for current or potential adverse effects.

Global ensemble projections reveal trophic amplification of ocean biomass declines with climate change.

While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends.

Starting a new anti-seizure medication in drug-resistant epilepsy: Add-on or substitute?

OBJECTIVES: Randomized studies in drug-resistant epilepsy (DRE) typically involve addition of a new anti-seizure medication (ASM). However, in clinical practice, if the patient is already taking multiple ASMs, then substitution of one of the current ASMs commonly occurs, despite little evidence supporting this approach. METHODS: Longitudinal prospective study of seizure outcome after commencing a previously untried ASM in patients with DRE. Multivariable time-to-event and logistic regression models were used to evaluate outcomes by whether the new ASM was introduced by addition or substitution. RESULTS: A total of 816 ASM changes in 436 adult patients with DRE between 2010 and 2018 were analyzed. The new ASM was added on 407 (50.1%) occasions and substituted on 409 (49.9%). Mean patient follow-up was 3.2 years. Substitution was more likely if the new ASM was enzyme-inducing or in patients with a greater number of concurrent ASMs. ASM add-on was more likely if a γ-aminobutyric acid (GABA) agonist was introduced or if the patient had previously trialed a higher number of ASMs. The rate of discontinuation due to lack of tolerability was similar between the add-on and substitution groups. No difference between the add-on and substitution ASM introduction strategies was observed for the primary outcome of ≥50% seizure reduction at 12 months. SIGNIFICANCE: Adding or substituting a new ASM in DRE has the same influence on seizure outcomes. The findings confirm that ASM alterations in DRE can be individualized according to concurrent ASM therapy and patient characteristics.

Short- and long-term outcomes of immediate and delayed treatment in epilepsy diagnosed after one or multiple seizures.

OBJECTIVES: To compare the outcomes between immediate and deferred treatments in patients diagnosed after one or multiple (two or more) seizures. METHODS: Our observational study investigated seizure recurrence and 12-month seizure remission in patients with newly diagnosed epilepsy, comparing immediate to deferred treatment in patients diagnosed after one seizure or after two or more seizures. RESULTS: Of 598 patients (62% male, median age 39 years), 347 (58%) were treated at diagnosis and 251 (42%) received deferred or no treatment. Seizure recurrence was higher with deferred treatment both in patients diagnosed after two or more seizures (n = 363; adjusted hazard ratio [aHR] = 2.38, 95% confidence interval [CI]: 1.79-3.14, p < 0.001) and after one seizure (n = 235; aHR = 1.41, 95% CI: 0.995-1.99, p = 0.05). Cumulative seizure recurrence rates at two years in patients diagnosed after two or more seizures were 73% with deferred treatment and 49% with immediate treatment (risk-factor-corrected number-needed-to-treat [NNT] = 4), and in those diagnosed after one seizure the rates were 60% and 51% (NNT = 8). Of 380 patients with eligible follow-up (median 4.3 years), 287 (76%) had been in seizure remission for at least one year and 211 (56%) remained in remission at last follow-up. Long-term remission rates were similar between immediate and deferred treatments, and between patients diagnosed after one seizure and those with two or more seizures. SIGNIFICANCE: Immediate rather than deferred treatment was less likely to influence seizure recurrence in patients diagnosed with epilepsy after a single seizure than in those diagnosed after two or more seizures, and showed no differences in long-term seizure freedom.

Treatment initiation decisions in newly diagnosed epilepsy-A longitudinal cohort study.

OBJECTIVE: To examine the factors and reasons influencing treatment initiation decisions in patients with newly diagnosed epilepsy. METHODS: We assessed antiseizure medication initiation decisions in adults with newly diagnosed epilepsy seen at first seizure clinics in Western Australia between 1999 and 2016 and followed to 2018. RESULTS: Of 610 patients (median age 40 years, 61.0% male), 426 (69.8%) were diagnosed after two or more seizures and 184 (30.2%) after a single seizure with risk factors for recurrence. Treatment was commenced in 427 patients (70.0%) at diagnosis, 112 (18.4%) during follow-up, mostly after further seizures, whereas 71 (11.6%) remained untreated at last follow-up. Elders (≥65 years, odds ratio [OR] = 3.06, 95% confidence interval [CI]: 1.62-5.80), more seizures (OR = 3.48, 95% CI: 2.03-5.96), and epileptogenic lesions on neuroimaging (OR = 2.15, 95% CI: 1.26-3.68) had a higher likelihood of treatment at diagnosis. Patients with less than one seizure per year within the preceding year (OR = 0.40, 95% CI: 0.21-0.73) and of higher socioeconomic status (OR = 0.985, 95% CI: 0.977-0.994) were less likely to be treated. For 93 patients (15.2%), treatment was not recommended at diagnosis, most commonly because only a single seizure had occurred. Ninety patients (14.8%) declined recommended treatment, mostly because they were unconvinced of the need for treatment or the diagnosis. SIGNIFICANCE: Thirty percent of adults with newly diagnosed epilepsy were not immediately treated. Treatment initiation in this real-world cohort was influenced by age, number of seizures prior to diagnosis, imaging findings, patient preferences, and socioeconomic status.

Time of Emergence and Large Ensemble Intercomparison for Ocean Biogeochemical Trends.

Anthropogenically forced changes in ocean biogeochemistry are underway and critical for the ocean carbon sink and marine habitat. Detecting such changes in ocean biogeochemistry will require quantification of the magnitude of the change (anthropogenic signal) and the natural variability inherent to the climate system (noise). Here we use Large Ensemble (LE) experiments from four Earth system models (ESMs) with multiple emissions scenarios to estimate Time of Emergence (ToE) and partition projection uncertainty for anthropogenic signals in five biogeochemically important upper-ocean variables. We find ToEs are robust across ESMs for sea surface temperature and the invasion of anthropogenic carbon; emergence time scales are 20-30 yr. For the biological carbon pump, and sea surface chlorophyll and salinity, emergence time scales are longer (50+ yr), less robust across the ESMs, and more sensitive to the forcing scenario considered. We find internal variability uncertainty, and model differences in the internal variability uncertainty, can be consequential sources of uncertainty for projecting regional changes in ocean biogeochemistry over the coming decades. In combining structural, scenario, and internal variability uncertainty, this study represents the most comprehensive characterization of biogeochemical emergence time scales and uncertainty to date. Our findings delineate critical spatial and duration requirements for marine observing systems to robustly detect anthropogenic change.

The other side of the leaf: Seizures associated with synthetic cannabinoid use.

There has recently been a marked rise in the medicinal use of cannabis for epilepsy and multiple other conditions. While seizures have been reported in association with synthetic cannabinoids, the clinical features and prognosis have not been studied. Thirty patients with a history of seizures occurring within 24 h of synthetic cannabinoid use were identified from a first seizure clinic database in Perth, Western Australia between 2011 and 2016. Eight had a prior history of seizures, three related to synthetic cannabinoid use, with an additional three patients having risk factors for seizures. The presenting event was a tonic-clonic seizure in 27 patients (90%). "Kronic" was the synthetic cannabinoid used by 16 patients. Absorption was via smoking in all cases, with seizures occurring within 30 min of inhalation in 14 patients (46%). Electroencephalography (EEG) showed epileptiform abnormalities in 11%, and neuroimaging revealed epileptogenic lesions in 12%. Nine of 24 patients with follow-up had subsequent seizures, occurring in the setting of further synthetic cannabinoid use in two patients. This seizure recurrence rate is similar to seizures provoked by other acute systemic insults. In conclusion, smoking of some synthetic cannabinoids is associated with seizures, and this may relate to an intrinsic proconvulsant effect.

Reconciling fisheries catch and ocean productivity.

Photosynthesis fuels marine food webs, yet differences in fish catch across globally distributed marine ecosystems far exceed differences in net primary production (NPP). We consider the hypothesis that ecosystem-level variations in pelagic and benthic energy flows from phytoplankton to fish, trophic transfer efficiencies, and fishing effort can quantitatively reconcile this contrast in an energetically consistent manner. To test this hypothesis, we enlist global fish catch data that include previously neglected contributions from small-scale fisheries, a synthesis of global fishing effort, and plankton food web energy flux estimates from a prototype high-resolution global earth system model (ESM). After removing a small number of lightly fished ecosystems, stark interregional differences in fish catch per unit area can be explained (r = 0.79) with an energy-based model that (i) considers dynamic interregional differences in benthic and pelagic energy pathways connecting phytoplankton and fish, (ii) depresses trophic transfer efficiencies in the tropics and, less critically, (iii) associates elevated trophic transfer efficiencies with benthic-predominant systems. Model catch estimates are generally within a factor of 2 of values spanning two orders of magnitude. Climate change projections show that the same macroecological patterns explaining dramatic regional catch differences in the contemporary ocean amplify catch trends, producing changes that may exceed 50% in some regions by the end of the 21st century under high-emissions scenarios. Models failing to resolve these trophodynamic patterns may significantly underestimate regional fisheries catch trends and hinder adaptation to climate change.

Mindfulness Meditation and Psychopathology.

Mindfulness meditation is increasingly incorporated into mental health interventions, and theoretical concepts associated with it have influenced basic research on psychopathology. Here, we review the current understanding of mindfulness meditation through the lens of clinical neuroscience, outlining the core capacities targeted by mindfulness meditation and mapping them onto cognitive and affective constructs of the Research Domain Criteria matrix proposed by the National Institute of Mental Health. We review efficacious applications of mindfulness meditation to specific domains of psychopathology including depression, anxiety, chronic pain, and substance abuse, as well as emerging efforts related to attention disorders, traumatic stress, dysregulated eating, and serious mental illness. Priorities for future research include pinpointing mechanisms, refining methodology, and improving implementation. Mindfulness meditation is a promising basis for interventions, with particular potential relevance to psychiatric comorbidity. The successes and challenges of mindfulness meditation research are instructive for broader interactions between contemplative traditions and clinical psychological science.

Satellite sensor requirements for monitoring essential biodiversity variables of coastal ecosystems.

The biodiversity and high productivity of coastal terrestrial and aquatic habitats are the foundation for important benefits to human societies around the world. These globally distributed habitats need frequent and broad systematic assessments, but field surveys only cover a small fraction of these areas. Satellite-based sensors can repeatedly record the visible and near-infrared reflectance spectra that contain the absorption, scattering, and fluorescence signatures of functional phytoplankton groups, colored dissolved matter, and particulate matter near the surface ocean, and of biologically structured habitats (floating and emergent vegetation, benthic habitats like coral, seagrass, and algae). These measures can be incorporated into Essential Biodiversity Variables (EBVs), including the distribution, abundance, and traits of groups of species populations, and used to evaluate habitat fragmentation. However, current and planned satellites are not designed to observe the EBVs that change rapidly with extreme tides, salinity, temperatures, storms, pollution, or physical habitat destruction over scales relevant to human activity. Making these observations requires a new generation of satellite sensors able to sample with these combined characteristics: (1) spatial resolution on the order of 30 to 100-m pixels or smaller; (2) spectral resolution on the order of 5 nm in the visible and 10 nm in the short-wave infrared spectrum (or at least two or more bands at 1,030, 1,240, 1,630, 2,125, and/or 2,260 nm) for atmospheric correction and aquatic and vegetation assessments; (3) radiometric quality with signal to noise ratios (SNR) above 800 (relative to signal levels typical of the open ocean), 14-bit digitization, absolute radiometric calibration <2%, relative calibration of 0.2%, polarization sensitivity <1%, high radiometric stability and linearity, and operations designed to minimize sunglint; and (4) temporal resolution of hours to days. We refer to these combined specifications as H4 imaging. Enabling H4 imaging is vital for the conservation and management of global biodiversity and ecosystem services, including food provisioning and water security. An agile satellite in a 3-d repeat low-Earth orbit could sample 30-km swath images of several hundred coastal habitats daily. Nine H4 satellites would provide weekly coverage of global coastal zones. Such satellite constellations are now feasible and are used in various applications.

Tropical nighttime warming as a dominant driver of variability in the terrestrial carbon sink.

The terrestrial biosphere is currently a strong carbon (C) sink but may switch to a source in the 21st century as climate-driven losses exceed CO2-driven C gains, thereby accelerating global warming. Although it has long been recognized that tropical climate plays a critical role in regulating interannual climate variability, the causal link between changes in temperature and precipitation and terrestrial processes remains uncertain. Here, we combine atmospheric mass balance, remote sensing-modeled datasets of vegetation C uptake, and climate datasets to characterize the temporal variability of the terrestrial C sink and determine the dominant climate drivers of this variability. We show that the interannual variability of global land C sink has grown by 50-100% over the past 50 y. We further find that interannual land C sink variability is most strongly linked to tropical nighttime warming, likely through respiration. This apparent sensitivity of respiration to nighttime temperatures, which are projected to increase faster than global average temperatures, suggests that C stored in tropical forests may be vulnerable to future warming.

Projections of climate-driven changes in tuna vertical habitat based on species-specific differences in blood oxygen affinity.

Oxygen concentrations are hypothesized to decrease in many areas of the ocean as a result of anthropogenically driven climate change, resulting in habitat compression for pelagic animals. The oxygen partial pressure, pO2 , at which blood is 50% saturated (P50 ) is a measure of blood oxygen affinity and a gauge of the tolerance of animals for low ambient oxygen. Tuna species display a wide range of blood oxygen affinities (i.e., P50 values) and therefore may be differentially impacted by habitat compression as they make extensive vertical movements to forage on subdaily time scales. To project the effects of end-of-the-century climate change on tuna habitat, we calculate tuna P50 depths (i.e., the vertical position in the water column at which ambient pO2 is equal to species-specific blood P50 values) from 21st century Earth System Model (ESM) projections included in the fifth phase of the Climate Model Intercomparison Project (CMIP5). Overall, we project P50 depths to shoal, indicating likely habitat compression for tuna species due to climate change. Tunas that will be most impacted by shoaling are Pacific and southern bluefin tunas-habitat compression is projected for the entire geographic range of Pacific bluefin tuna and for the spawning region of southern bluefin tuna. Vertical shifts in P50 depths will potentially influence resource partitioning among Pacific bluefin, bigeye, yellowfin, and skipjack tunas in the northern subtropical and eastern tropical Pacific Ocean, the Arabian Sea, and the Bay of Bengal. By establishing linkages between tuna physiology and environmental conditions, we provide a mechanistic basis to project the effects of anthropogenic climate change on tuna habitats.

Is the first seizure epilepsy--and when?

OBJECTIVE: Epilepsy has recently been redefined to include a single unprovoked seizure if the probability of recurrence is ≥60% over the following 10 years. This definition is based on the estimated risk of a third seizure after two unprovoked seizures, using the lower-limit 95% confidence interval (CI) at 4 years, and does not account for the initially high recurrence rate after first-ever seizure that rapidly falls with increasing duration of seizure freedom. We analyzed long-term outcomes after the first-ever seizure, and the influence of duration of seizure freedom on the likelihood of seizure recurrence, and their relevance to the new definition of epilepsy. METHODS: Prospective analysis of 798 adults with a first-ever unprovoked seizure seen at a hospital-based first seizure clinic between 2000 and 2011. The likelihood of seizure recurrence was analyzed according to the duration of seizure freedom, etiology, electroencephalography (EEG), and neuroimaging findings. RESULTS: The likelihood of seizure recurrence at 10 years was ≥60% in patients with epileptiform abnormalities on EEG or neuroimaging abnormalities, therefore, meeting the new definition of epilepsy. However, the risk of recurrence was highly time dependent; after a brief period (≤12 weeks) of seizure freedom, no patient group continued to fulfill the new definition of epilepsy. Of 407 patients who had a second seizure, the likelihood of a third seizure at 4 years was 68% (95% CI 63-73%) and at 10 years was 85% (95% CI 79-91%). SIGNIFICANCE: The duration of seizure freedom following first-ever seizure substantially influences the risk of recurrence, with none of our patients fulfilling the new definition of epilepsy after a short period of seizure freedom. When a threshold was applied based on the 10-year risk of a third seizure from our data, no first-seizure patient group ever had epilepsy. These data may be utilized in a definition of epilepsy after a first-ever seizure.