The management of sepsis has substantially improved over the past 15 years. In this study, early, goal-directed therapy, which focuses on the initial resuscitation efforts, was compared with usual ...care for the management of severe sepsis in the United Kingdom.
The incidence of severe sepsis and septic shock in adults is estimated to range from 56 to 91 per 100,000 population per year.
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Affected patients have high rates of death, complications, and resource utilization.
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Since 2002, the Surviving Sepsis Campaign (SSC) has promoted best practice, including early recognition, source control, appropriate and timely antibiotic administration, and resuscitation with intravenous fluids and vasoactive drugs.
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Resuscitation guidance is largely based on a 2001 single-center, proof-of-concept study by Rivers et al., which indicated that protocolized delivery of 6 hours of early, goal-directed therapy (EGDT) to patients presenting to the emergency department . . .
Impact ejecta emplacement on terrestrial planets Osinski, Gordon R.; Tornabene, Livio L.; Grieve, Richard A.F.
Earth and planetary science letters,
10/2011, Letnik:
310, Številka:
3
Journal Article
Recenzirano
Impact cratering is one of the most fundamental processes responsible for shaping the surfaces of solid planetary bodies. One of the principal characteristics of impact events is the formation and ...emplacement of ejecta deposits, an understanding of which is critical for planetary exploration. Current models of ejecta emplacement, however, do not account for several important observations of ejecta deposits on the terrestrial planets, in particular, the presence of more than one layer of ejecta. Furthermore, there is also no universal model for the origin and emplacement of ejecta on different planetary bodies. We present a unifying working hypothesis for the origin and emplacement of ejecta on the terrestrial planets, in which the ejecta are emplaced in a multi-stage process. The generation of the continuous ejecta blanket occurs during the excavation stage of cratering, via the conventional ballistic sedimentation and radial flow model. This is followed by the emplacement of more melt-rich, ground-hugging flows – the “surface melt flow” phase – during the terminal stages of crater excavation and the modification stage of crater formation. Minor fallback occurs during the final stages of crater formation. Several factors will affect the final morphology and character of ejecta deposits. The volatile content and cohesiveness of the uppermost target rocks will significantly affect the runout distance of the ballistically emplaced continuous ejecta blanket, with impact angle also influencing the overall geometry of the deposits (e.g., the production of the characteristic butterfly pattern seen in very oblique impacts). Ejecta deposited during the surface melt flow stage is influenced by several factors, most importantly planetary gravity, surface temperature, and the physical properties of the target rocks. Topography and angle of impact play important roles in determining the final distribution of surface melt flow ejecta deposits with respect to the source crater. This working hypothesis of ballistic sedimentation and surface melt flow provides a framework in which observations of ejecta at impact craters can be compared and placed in the context of the respective terrestrial planets.
►A new working hypothesis for impact ejecta emplacement is provided. ►Observations from Earth, Moon, Mars, Mercury and Venus are synthesized. ►Impact ejecta are emplaced in a multi-stage process. ►The emplacement of late stage surface melt flows is shown to be important. ►Different ejecta layers sample different depths in planetary crusts.
The Cretaceous-Paleogene boundary approximately 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large ...asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction.
Large meteorite impact structures on the terrestrial bodies of the Solar System contain pronounced topographic rings, which emerged from uplifted target (crustal) rocks within minutes of impact. To ...flow rapidly over large distances, these target rocks must have weakened drastically, but they subsequently regained sufficient strength to build and sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial cratering, followed by increasingly localized faulting.
IMPORTANCE: Vasopressors are commonly administered to intensive care unit (ICU) patients to raise blood pressure. Balancing risks and benefits of vasopressors is a challenge, particularly in older ...patients. OBJECTIVE: To determine whether reducing exposure to vasopressors through permissive hypotension (mean arterial pressure MAP target, 60-65 mm Hg) reduces mortality at 90 days in ICU patients aged 65 years or older with vasodilatory hypotension. DESIGN, SETTING, AND PARTICIPANTS: A multicenter, pragmatic, randomized clinical trial was conducted in 65 ICUs in the United Kingdom and included 2600 randomized patients aged 65 years or older with vasodilatory hypotension (assessed by treating clinician). The study was conducted from July 2017 to March 2019, and follow-up was completed in August 2019. INTERVENTIONS: Patients were randomized 1:1 to vasopressors guided either by MAP target (60-65 mm Hg, permissive hypotension) (n = 1291) or according to usual care (at the discretion of treating clinicians) (n = 1307). MAIN OUTCOME AND MEASURES: The primary clinical outcome was all-cause mortality at 90 days. RESULTS: Of 2600 randomized patients, after removal of those who declined or had withdrawn consent, 2463 (95%) were included in the analysis of the primary outcome (mean SD age 75 years 7 years; 1387 57% men). Patients randomized to the permissive hypotension group had lower exposure to vasopressors compared with those in the usual care group (median duration 33 hours vs 38 hours; difference in medians, –5.0; 95% CI, –7.8 to –2.2 hours; total dose in norepinephrine equivalents median, 17.7 mg vs 26.4 mg; difference in medians, –8.7 mg; 95% CI, –12.8 to −4.6 mg). At 90 days, 500 of 1221 (41.0%) in the permissive hypotension compared with 544 of 1242 (43.8%) in the usual care group had died (absolute risk difference, −2.85%; 95% CI, −6.75 to 1.05; P = .15) (unadjusted relative risk, 0.93; 95% CI, 0.85-1.03). When adjusted for prespecified baseline variables, the odds ratio for 90-day mortality was 0.82 (95% CI, 0.68 to 0.98). Serious adverse events were reported for 79 patients (6.2%) in the permissive care group and 75 patients (5.8%) in the usual care group. The most common serious adverse events were acute renal failure (41 3.2% vs 33 2.5%) and supraventricular cardiac arrhythmia (12 0.9% vs 13 1.0%). CONCLUSIONS AND RELEVANCE: Among patients 65 years or older receiving vasopressors for vasodilatory hypotension, permissive hypotension compared with usual care did not result in a statistically significant reduction in mortality at 90 days. However, the confidence interval around the point estimate for the primary outcome should be considered when interpreting the clinical importance of the study. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN10580502
This study presents a patient-level meta-analysis of three recent trials of early, goal-directed therapy for septic shock. Results showed that EGDT did not improve outcomes and increased ...hospitalization costs across a broad range of patient and hospital characteristics.
In 2001, Rivers and colleagues reported on a 263-patient, single-center, randomized, controlled trial of early, goal-directed therapy (EGDT) versus usual care in patients presenting with septic shock to an urban emergency department in the United States.
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EGDT is a 6-hour resuscitation protocol for the administration of intravenous fluids, vasopressors, inotropes, and red-cell transfusion to achieve prespecified targets for arterial blood pressure, central venous pressure, central venous oxygen saturation, and hemoglobin level. EGDT reduced hospital mortality from 46.5% to 30.5%,
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prompting many institutions worldwide to adopt EGDT.
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Three subsequent, government-funded, multicenter, randomized, controlled trials from the United States (Protocolized Care for . . .
The Offset Dykes are impact melt-bearing dykes related to the 1.85 Ga Sudbury impact structure. Currently, the dykes extend radially outward from-or occur concentrically around-the Sudbury Igneous ...Complex, which is the remnant of a differentiated impact melt sheet and the source of the dykes. The recently identified three Pele Offset Dykes intrude into the Archean rocks north of the Sudbury Igneous Complex. In this study, the Pele dykes are characterized for the first time by a combination of fieldwork, optical microscopy, electron microprobe analyses, and bulk geochemical analyses. The Pele Offset Dykes stand out from the other Offset Dykes at Sudbury in two significant ways: (i) All other known Offset Dykes consist of an inclusion-rich lithology in the center of the dyke and an inclusion-poor lithology along the margins. The Pele dykes, however, are only composed of the inclusion-poor phase. (ii) The Pele dykes-particularly the Central and Eastern dykes-have a more evolved chemical composition relative to the other Offset Dykes. These observations suggest that the Pele dykes were emplaced after the other known Offset Dykes during two injection events: the Western followed by the Central and Eastern Pele dykes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The first day of the Cenozoic Gulick, Sean P. S.; Bralower, Timothy J.; Ormö, Jens ...
Proceedings of the National Academy of Sciences - PNAS,
09/2019, Letnik:
116, Številka:
39
Journal Article
Recenzirano
Odprti dostop
Highly expanded Cretaceous-Paleogene (K-Pg) boundary section from the Chicxulub peak ring, recovered by International Ocean Discovery Program (IODP)-International Continental Scientific Drilling ...Program (ICDP) Expedition 364, provides an unprecedented window into the immediate aftermath of the impact. Site M0077 includes ∼130 m of impact melt rock and suevite deposited the first day of the Cenozoic covered by <1 m of micrite-rich carbonate deposited over subsequent weeks to years. We present an interpreted series of events based on analyses of these drill cores. Within minutes of the impact, centrally uplifted basement rock collapsed outward to forma peak ring capped in melt rock. Within tens of minutes, the peak ring was covered in ∼40 m of brecciated impact melt rock and coarsegrained suevite, including clasts possibly generated by melt-water interactions during ocean resurge. Within an hour, resurge crested the peak ring, depositing a 10-m-thick layer of suevite with increased particle roundness and sorting.Within hours, the full resurge deposit formed through settling and seiches, resulting in an 80-m-thick fining-upward, sorted suevite in the flooded crater. Within a day, the reflected rim-wave tsunami reached the crater, depositing a cross-bedded sand-to-fine gravel layer enriched in polycyclic aromatic hydrocarbons overlain by charcoal fragments. Generation of a deep crater open to the ocean allowed rapid flooding and sediment accumulation rates among the highest known in the geologic record. The high-resolution section provides insight into the impact environmental effects, including charcoal as evidence for impactinduced wildfires and a paucity of sulfur-rich evaporites from the target supporting rapid global cooling and darkness as extinction mechanisms.
Observational and logical arguments are presented for the lithology formerly named the Garson Member of the Onaping Formation being the clast‐bearing, fine‐grained, chilled Upper Contact Unit (UCU) ...of the Sudbury Igneous Complex (SIC) in the Garson region of the Sudbury impact structure. It differs considerably, however, from the UCU in the North Range of the SIC with respect to the character of its clasts. Namely, the clasts are essentially monomict (quartzites), much larger (up to 100 m across), and much more abundant (up to 80% in places). These differences indicate a different source than “fallback” material for the clasts in the UCU in the Garson region. Their character requires a “coherent,” singular source that was topographically above the SIC melt pool. Such a source would correspond to that of an emergent peak ring of fractured target rocks. The clasts are identified as Huronian Mississagi quartzite, which is estimated to have been at a nominal depth of 7.5 ± 2.5 km at the time of impact. This provides a constraint on the depth of origin of the peak ring. This depth estimate is closest to the lower depth estimate from current numerical models of Sudbury and the similar‐sized Chicxulub impact structures.
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