Surgical procedures are frequently introduced into general practice on the basis of uncontrolled studies that are less rigorous than those required for the approval of medical interventions.
1
The ...standard for the evaluation of surgical therapy is lower because of the complexity of designing and conducting scientifically valid and ethically acceptable clinical trials of surgical procedures.
2
As a result, many surgical trials fail to control for investigator bias or placebo effects.
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,
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The list of inadequately studied invasive or surgical procedures that became part of standard medical practice only to be abandoned after closer scrutiny includes bloodletting, routine tonsillectomy, routine circumcision, . . .
Bioturbation, the biogenic modification of sediments through particle reworking and burrow ventilation, is a key mediator of many important geochemical processes in marine systems. In situ ...quantification of bioturbation can be achieved in a myriad of ways, requiring expert knowledge, technology, and resources not always available, and not feasible in some settings. Where dedicated research programmes do not exist, a practical alternative is the adoption of a trait‐based approach to estimate community bioturbation potential (BPc). This index can be calculated from inventories of species, abundance and biomass data (routinely available for many systems), and a functional classification of organism traits associated with sediment mixing (less available). Presently, however, there is no agreed standard categorization for the reworking mode and mobility of benthic species. Based on information from the literature and expert opinion, we provide a functional classification for 1033 benthic invertebrate species from the northwest European continental shelf, as a tool to enable the standardized calculation of BPc in the region. Future uses of this classification table will increase the comparability and utility of large‐scale assessments of ecosystem processes and functioning influenced by bioturbation (e.g., to support legislation). The key strengths, assumptions, and limitations of BPc as a metric are critically reviewed, offering guidelines for its calculation and application.
Bioturbation, the biogenic modification of sediments, is a key mediator of geochemical processes in marine systems. Where dedicated bioturbation research programs do not exist, community BPc – a functional metric for bioturbation well established in the literature (BPc) – can be calculated from inventories of species, abundance and biomass data (routinely available), and a functional classification of organism traits associated with sediment mixing (less available). Here, the ICES Study Group on Climate Related Benthic Processes in the North Sea offers a standardized functional classification for bioturbation for 1032 NW European marine invertebrate species to estimate BPc, providing a critical review of the strengths and limitations of this functional approach.
Elevated atmospheric CO2 can change foliar tissue chemistry. This alters leaf litter palatability to macroinvertebrate detritivores with consequences for decomposition, nutrient turnover, and ...food-web structure. Currently there is no consensus on the link between CO2 enrichment, litter chemistry, and macroinvertebrate-mediated leaf decomposition. To identify any unifying mechanisms, we presented eight invertebrate species from aquatic and terrestrial ecosystems with litter from Alnus glutinosa (common alder) or Betula pendula (silver birch) trees propagated under ambient (380 ppm) or elevated (ambient +200 ppm) CO2 concentrations. Alder litter was largely unaffected by CO2 enrichment, but birch litter from leaves grown under elevated CO2 had reduced nitrogen concentrations and greater C/N ratios. Invertebrates were provided individually with either (i) two litter discs, one of each CO2 treatment ('choice'), or (ii) one litter disc of each CO2 treatment alone ('no-choice'). Consumption was recorded. Only Odontocerum albicorne showed a feeding preference in the choice test, consuming more ambient- than elevated-CO2 birch litter. Species' responses to alder were highly idiosyncratic in the no-choice test: Gammarus pulex and O. albicorne consumed more elevated-CO2 than ambient-CO2 litter, indicating compensatory feeding, while Oniscus asellus consumed more of the ambient-CO2 litter. No species responded to CO2 treatment when fed birch litter. Overall, these results show how elevated atmospheric CO2 can alter litter chemistry, affecting invertebrate feeding behaviour in species-specific ways. The data highlight the need for greater species-level information when predicting changes to detrital processing-a key ecosystem function-under atmospheric change.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Ducted fuel injection (DFI) is a novel fuel injection scheme which has been shown to mitigate soot formation in mixing-controlled compression-ignition (MCCI) engines, while not producing more NOx. ...However, the underlying physical phenomena leading to soot reduction in DFI are not well understood. To better understand these mechanisms, DFI and free sprays were studied in a high-pressure vessel across various conditions and geometries using optical diagnostics. Schlieren imaging, OH* chemiluminescence, and broadband luminosity were used to characterize the reacting flow, while 2D laser absorption and scattering (LAS) was used to quantify the non-reacting mixing fields. The experiments show that the duct leads to enhanced air entrainment upstream of the theoretical impingement point between the duct and spray, i.e. the jet-pumping effect; that DFI mitigates soot formation by creating a leaner mixture at the lift-off length; that injection pressure does not have a significant impact on the mixing field for a given DFI configuration; and that a reduction in residence time for soot formation between the lift-off length and soot oxidation, influenced by injection pressure, is another driver for DFI performance. Overall, this study provides solid evidence of the physical mechanisms by which DFI reduces soot, enabling future optimization of design and operation.
Purpose
Two randomized trials published in 2001 provided level 1 evidence for the use of cytoreductive nephrectomy (CyNx) for the treatment of metastatic renal cell carcinoma (mRCC). However, the ...regulatory approval of vascular endothelial growth factor tyrosine kinase inhibitors (VEGFR-TKI) in 2005 has left an “evidence void” regarding the use of CyNx. We evaluated the patterns in the use of CyNx in the cytokine and VEGFR-TKI eras, and the patient characteristics associated with the use of CyNx.
Methods
The Surveillance, Epidemiology, and End Results registry was used to identify patients with histologically or cytologically confirmed stage IV RCC between 2001 and 2008. Patients were classified as treated during the cytokine (2001–2005) or VEGFR-TKI (2006–2008) eras. A multivariate logistic regression analysis was performed to calculate the odds of undergoing CyNx according to treatment era and socioeconomic characteristics.
Results
Overall, 1,112 of 2,448 patients (45 %) underwent CyNx. CyNx use remained stable between 2001 and 2005 (50 %), but decreased to 38 % in 2008. Logistic regression analysis revealed that older age (OR 0.82, 95 % CI: 0.68, 0.99), black race (OR 0.64, 95 % CI: 0.46, 0.91), Hispanic ethnicity (OR 0.71, 95 % CI: 0.54, 0.93), and treatment in the VEGFR-TKI era (OR 0.82, 95 % CI: 0.68, 0.99) were independently associated with decreased use of CyNx.
Conclusions
Use of CyNx in the United States has declined in the VEGFR-TKI era. Older patients and minorities are less likely to receive CyNx. Results of ongoing phase III trials are needed to refine the role of this treatment modality.
Arctic marine ecosystems are undergoing a series of major rapid adjustments to the regional amplification of climate change, but there is a paucity of knowledge about how changing environmental ...conditions might affect reproductive cycles of seafloor organisms. Shifts in species reproductive ecology may influence their entire life-cycle, and, ultimately, determine the persistence and distribution of taxa. Here, we investigate whether the combined effects of warming and ocean acidification based on near-future climate change projections affects the reproductive processes in benthic bivalves (
Astarte crenata
and
Bathyarca glacialis
) from the Barents Sea. Both species present large oocytes indicative of lecithotrophic or direct larval development after ∼4 months exposure to ambient <2°C, ∼400 ppm (CO
2
) and near-future 3–5°C, ∼550 ppm (CO
2
) conditions, but we find no evidence that the combined effects of acidification and warming affect the size frequency distribution of oocytes. Whilst our observations are indicative of resilience of this reproductive stage to global changes, we also highlight that the successful progression of gametogenesis under standard laboratory conditions does not necessarily mean that successful development and recruitment will occur in the natural environment. This is because the metabolic costs of changing environmental conditions are likely to be offset by, as is common practice in laboratory experiments, feeding
ad libitum
. We discuss our findings in the context of changing food availability in the Arctic and conclude that, if we are to establish the vulnerability of species and ecosystems, there is a need for holistic approaches that incorporate multiple system responses to change.
Regulation of research on microbes that cause disease in humans has historically been focused on taxonomic lists of 'bad bugs'. However, given our increased knowledge of these pathogens through ...inexpensive genome sequencing, 5 decades of research in microbial pathogenesis, and the burgeoning capacity of synthetic biologists, the limitations of this approach are apparent. With heightened scientific and public attention focused on biosafety and biosecurity, and an ongoing review by US authorities of dual-use research oversight, this article proposes the incorporation of sequences of concern (SoCs) into the biorisk management regime governing genetic engineering of pathogens. SoCs enable pathogenesis in all microbes infecting hosts that are 'of concern' to human civilization. Here we review the functions of SoCs (FunSoCs) and discuss how they might bring clarity to potentially problematic research outcomes involving infectious agents. We believe that annotation of SoCs with FunSoCs has the potential to improve the likelihood that dual use research of concern is recognized by both scientists and regulators before it occurs.
(1) Elevated atmospheric CO2 (eCO2) may affect organic inputs to woodland soils with potential consequences for C dynamics and associated aggregation; (2) The Bangor Free Air Concentration Enrichment ...experiment compared ambient (330 ppmv) and elevated (550 ppmv) CO2 regimes over four growing seasons (2005–2008) under Alnus glutinosa, Betula pendula and Fagus sylvatica. Litter from the experiment (autumn 2008) and Lumbricus terrestris were added to mesocosm soils. Microbial properties and aggregate stability were investigated in soil and earthworm casts. Soils taken from the field experiment in spring 2009 were also investigated; (3) eCO2 litter had lower N and higher C:N ratios. F. sylvatica and B. pendula litter had lower N and P than A. glutinosa; F. sylvatica had higher cellulose. In mesocosms, eCO2 litter decreased respiration, mineralization constant (respired C:total organic C) and soluble carbon in soil but not earthworm casts; microbial‐C and fungal hyphal length differed by species (A. glutinosa = B. pendula > F. sylvatica) not CO2 regime. eCO2 increased respiration in field aggregates but increased stability only under F. sylvatica; (4) Lower litter quality under eCO2 may restrict its initial decomposition, affecting C stabilization in aggregates. Later resistant materials may support microbial activity and increase aggregate stability. In woodland, C and soil aggregation dynamics may alter under eCO2, but outcomes may be influenced by tree species and earthworm activity.
The impact of warming, acidification, and deoxygenation on deep-sea environments is a growing concern. Historical records are sparse, particularly at high latitudes, making climate change projections ...challenging. Indirect proxies, such as trace element composition of marine carbonates, such as coral skeletons, can offer an alternative method to fill data gaps but have not been realised. Here, using Laser Ablation Triple-Quadrupole Inductively Coupled Plasma Mass Spectrometry (LA-QQQ-ICP-MS), we examined micrometre-scale element variation within and between individual colonies of the bamboo coral Keratoisis sp. obtained from the Eastern Canadian Arctic. These data are used to assess the influence of biological variability on geochemical tracers for reconstructing past environmental conditions (temperature: Mg/Ca, Li/Mg, Sr/Ca, Ba/Ca, U/Ca; BaSW: Ba/Ca). We place these data into context, based on a survey of literature data, using refined calibrations for high-Mg calcitic Octocorals. We find reproducible (2σ relative coefficient of variation) values of Mg/Ca (3%) and Ba/Ca (6%) along the radial growth axis of all colonies and internodes of Keratoisis sp., indicating that these signals are likely suitable for environmental reconstructions. After revising the available multi-taxa calibrations for Mg/Ca (0.316 ± 0.026 °C/mmol/mol, R2 = 0.87, p < 0.001) and Ba/Ca (Ba/Ca μmol/mol = 0.148 ± 0.005 BaSW nmol/kg, R2 = 0.97, p < 0.001), we show that vital effects within and among Keratoisis sp. colonies strongly influence reconstructed temperature and BaSW, but this can be somewhat mitigated by combining multiple internode transects from one colony into a single composite series. Despite the ontogenetic variability, all colonies reveal a gradual deep-water cooling trend since the early 21st century and synchronised, multi-year spikes in Ba/Ca (and hence BaSW) that suggest substantial and coherent barium inputs to the seafloor. Our study confirms the reliability of Mg/Ca and Ba/Ca proxies in high-Mg bamboo corals for detecting multi-annual temperature and seawater barium variations in cold-water environments, but further investigation into micro-scale element behaviour influenced by biotic processes in these corals is needed to enhance confidence in reconstructions at finer spatial and temporal resolutions. We conclude that employing empirical calibrations based on multi-taxa approaches can increase the certainty of capturing regional changes in the environment more accurately than a single species calibration, while leveraging multiple element series to account for biological-induced variability improves single colony reconstructions.
•Trace element patterns in Arctic Keratoisis vary between and within colonies.•Leveraging element patterns across internodes improves reproducibility of signals.•Integrating intra-specificity in living proxies enhances deep-water reconstructions.
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