•Landsystem science produced many empirical results but lacks progress in theory.•We review theories on causes of changes in land use extent and intensity.•We synthesize middle-range theories of ...systemic land system processes.•Theories of land-use spillovers (land sparing and rebound effects with intensification, leakage).•Theories of land-use transitions (structural non-linear changes, including forest transition).
Changes in land systems generate many sustainability challenges. Identifying more sustainable land-use alternatives requires solid theoretical foundations on the causes of land-use/cover changes. Land system science is a maturing field that has produced a wealth of methodological innovations and empirical observations on land-cover and land-use change, from patterns and processes to causes. We take stock of this knowledge by reviewing and synthesizing the theories that explain the causal mechanisms of land-use change, including systemic linkages between distant land-use changes, with a focus on agriculture and forestry processes. We first review theories explaining changes in land-use extent, such as agricultural expansion, deforestation, frontier development, and land abandonment, and changes in land-use intensity, such as agricultural intensification and disintensification. We then synthesize theories of higher-level land system change processes, focusing on: (i) land-use spillovers, including land sparing and rebound effects with intensification, leakage, indirect land-use change, and land-use displacement, and (ii) land-use transitions, defined as structural non-linear changes in land systems, including forest transitions. Theories focusing on the causes of land system changes span theoretically and epistemologically disparate knowledge domains and build from deductive, abductive, and inductive approaches. A grand, integrated theory of land system change remains elusive. Yet, we show that middle-range theories – defined here as contextual generalizations that describe chains of causal mechanisms explaining a well-bounded range of phenomena, as well as the conditions that trigger, enable, or prevent these causal chains –, provide a path towards generalized knowledge of land systems. This knowledge can support progress towards sustainable social-ecological systems.
Does maternal infection with severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) in first trimester pregnancy have an impact on the fetal development as measured by nuchal translucency ...thickness and pregnancy loss?
Nuchal translucency thickness at the first trimester scan was not significantly different in pregnant women with versus without SARS-CoV-2 infection in early pregnancy and there was no significantly increased risk of pregnancy loss in women with SARS-CoV-2 infection in the first trimester.
Pregnant women are more vulnerable to viral infections. Previous coronavirus epidemics have been associated with increased maternal morbidity, mortality and adverse obstetric outcomes. Currently, no evidence exists regarding possible effects of SARS-CoV-2 in first trimester pregnancies.
Cohort study of 1019 women with a double test taken between 17 February and 23 April 2020, as a part of the combined first trimester risk assessment, and 36 women with a first trimester pregnancy loss between 14 April and 21 May 2020, prior to the double test. The study period was during the first SARS-CoV-2 epidemic wave in Denmark.
Cohort 1 included pregnant women with a double test taken within the study period. The excess serum from each double test was analyzed for SARS-CoV-2 antibodies. Results were correlated to the nuchal translucency thickness and the number of pregnancy losses before or at the time of the first trimester scan. Cohort 2 included women with a pregnancy loss before the gestational age for double test sample. Serum from a blood test taken the day the pregnancy loss was identified was analyzed for SARS-CoV-2 antibodies. The study was conducted at a public university hospital serving ∼12% of pregnant women and births in Denmark. All participants in the study provided written informed consent.
Eighteen (1.8%) women had SARS-CoV-2 antibodies in the serum from the double test suggestive of SARS-CoV-2 infection in early pregnancy. There was no significant difference in nuchal translucency thickness for women testing positive for previous SARS-CoV-2 infection (n = 16) versus negative (n = 966) (P = 0.62). There was no significantly increased risk of pregnancy loss for women with antibodies (n = 1) (OR 3.4, 0.08-24.3 95% CI, P = 0.27). None of the women had been hospitalized due to SARS-CoV-2 infection. None of the women with pregnancy loss prior to the double test (Cohort 2) had SARS-CoV-2 antibodies.
These results may only apply to similar populations and to patients who do not require hospitalization due to SARS-CoV-2 infection. A limitation of the study is that only 1.8% of the study population had SARS-CoV-2 antibodies suggestive of previous infection.
Maternal SARS-CoV-2 infection had no effect on the nuchal translucency thickness and there was no significantly increased risk of pregnancy loss for women with SARS-CoV-2 infection in first trimester pregnancy. Evidence concerning COVID-19 in pregnancy is still limited. These data indicate that infection with SARS-CoV-2 in not hospitalized women does not pose a significant threat in first trimester pregnancies. Follow-up studies are needed to establish any risk to a fetus exposed to maternal SARS-CoV-2 infection.
Prof. H.S.N. and colleagues received a grant from the Danish Ministry of Research and Education for research of COVID-19 among pregnant women. The Danish government was not involved in the study design, data collection, analysis, interpretation of data, writing of the report or decision to submit the paper for publication. A.I., J.O.-L., J.B.-R., D.M.S., J.E.-F. and E.R.H. received funding from a Novo Nordisk Foundation (NNF) Young Investigator Grant (NNF15OC0016662) and a Danish National Science Foundation Center Grant (6110-00344B). A.I. received a Novo Scholarship. J.O.-L. is funded by an NNF Pregraduate Fellowship (NNF19OC0058982). D.W. is funded by the NNF (NNF18SA0034956, NNF14CC0001, NNF17OC0027594). A.M.K. is funded by a grant from the Rigshospitalet's research fund. H.S.N. has received speaker's fees from Ferring Pharmaceuticals, Merck Denmark A/S and Ibsa Nordic (outside the submitted work). N.l.C.F. has received a grant from Gedeon Richter (outside the submitted work). A.M.K. has received speaker's fee from Merck (outside the submitted work). The other authors did not report any potential conflicts of interest.
N/A.
Physics prospects for ATLAS at the HL-LHC Nielsen, J
Journal of physics. Conference series,
12/2020, Letnik:
1690, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Abstract
The ATLAS experiment at CERN will undergo a series of detector upgrades over the next few years to prepare for the the High-Luminosity Large Hadron Collider (HL-LHC) project. The upgrades ...are designed to maintain or improve detector performance, even with the instantaneous luminosity needed to deliver a total of 3000 fb
−1
of proton-proton collision data at
s
=
14
TeV
to ATLAS. This contribution provides details of the broad and deep program of measurements and searches planned by ATLAS for the HL-LHC. The higher centre-of-mass energy and increased integrated luminosity will allow ATLAS not only to improve the precision of Higgs boson, electroweak boson, and top quark measurements, but also to extend the sensitivity of searches for beyond-the-Standard-Model processes with small cross sections. Many of the projections use detailed detector simulations to model the performance of the proposed ATLAS detector upgrades.
With the massive consumption of fossil fuels and its detrimental impact on the environment, methods of generating clean power are urgent. Hydrogen is an ideal carrier for renewable energy; however, ...hydrogen generation is inefficient because of the lack of robust catalysts that are substantially cheaper than platinum. Therefore, robust and durable earth-abundant and cost-effective catalysts are desirable for hydrogen generation from water splitting via hydrogen evolution reaction. Here we report an active and durable earth-abundant transition metal dichalcogenide-based hybrid catalyst that exhibits high hydrogen evolution activity approaching the state-of-the-art platinum catalysts, and superior to those of most transition metal dichalcogenides (molybdenum sulfide, cobalt diselenide and so on). Our material is fabricated by growing ternary molybdenum sulfoselenide particles on self-standing porous nickel diselenide foam. This advance provides a different pathway to design cheap, efficient and sizable hydrogen-evolving electrode by simultaneously tuning the number of catalytic edge sites, porosity, heteroatom doping and electrical conductivity.
In the mid‐1970s, it was recognized that chlorofluorocarbons (CFCs) were strong greenhouse gases that could have substantial impacts on radiative forcing of climate change, as well as being ...substances that deplete stratospheric ozone. Around a decade later, this group of radiatively active compounds was expanded to include a large number of replacements for ozone‐depleting substances such as chlorocarbons, hydrochlorocarbons, hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), bromofluorocarbons, and bromochlorofluorocarbons. This paper systematically reviews the published literature concerning the radiative efficiencies (REs) of CFCs, bromofluorocarbons and bromochlorofluorocarbons (halons), HCFCs, HFCs, PFCs, sulfur hexafluoride, nitrogen trifluoride, and related halogen containing compounds. In addition, we provide a comprehensive and self‐consistent set of new calculations of REs and global warming potentials (GWPs) for these compounds, mostly employing atmospheric lifetimes taken from the available literature. We also present global temperature change potentials for selected gases. Infrared absorption spectra used in the RE calculations were taken from databases and individual studies and from experimental and ab initio computational studies. Evaluations of REs and GWPs are presented for more than 200 compounds. Our calculations yield REs significantly (> 5%) different from those in the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) for 49 compounds. We present new RE values for more than 100 gases which were not included in AR4. A widely used simple method to calculate REs and GWPs from absorption spectra and atmospheric lifetimes is assessed and updated. This is the most comprehensive review of the radiative efficiencies and global warming potentials of halogenated compounds performed to date.
Key Points
We review REs of CFCs,Bromocarbons and halons, HCFCs,HFCs,PFCs, SF6,NF3.
We present calculations of REs and GWPs for these compounds.
We present Global Temperature change Potentials (GTPs) for selected gases.
Background: Use of ultrasound by anaesthesiologists performing regional blocks is rapidly gaining popularity. The aims of this review were to summarize and update accumulating evidence on ...ultrasound‐guided nerve blocks, with an emphasis on the clinical relevance of the results and to critically appraise changing standards in regional anaesthesia.
Methods: A search of MEDLINE and EMBASE (1966 to 31 December 2007) was conducted using the following free terms: ‘ultrasound and regional anesthesia’, ‘ultrasound and peripheral block’ and ‘ultrasound and nerve and block’. These were combined with the MESH terms ‘nerve block’ and ‘ultrasonography’. The following limits were applied: studies with s, only in humans, published in core clinical journals. Trial type: meta‐analysis, randomized‐controlled trial and clinical trial.
Results: When peripheral nerves are adequately imaged by ultrasound, the concomitant use of nerve stimulation offers no further advantage. However, several studies reported problems with obtaining satisfactory images in some patients. Ultrasound guidance significantly shortened the block performance time and/or reduced the number of needle passes to reach the target in all comparative studies. The occurrence of paraesthesia during block performance was also reduced, but not the incidence of short‐lasting post‐operative neuropraxia. The frequency of accidental vascular punctures may be lower, but the data are contradictory. Block onset time was significantly shortened. Block duration was longer in children, but not in adults. Ultrasound also allowed dose reduction of the local anaesthetic (LA).
Conclusions: Ultrasound guidance shortens the block performance time, reduces the number of needle passes and shortens the block onset time. Blocks may be performed using lower LA doses.
Sample preparation for high-throughput sequencing (HTS) includes treatment with various laboratory components, potentially carrying viral nucleic acids, the extent of which has not been thoroughly ...investigated. Our aim was to systematically examine a diverse repertoire of laboratory components used to prepare samples for HTS in order to identify contaminating viral sequences.
A total of 322 samples of mainly human origin were analysed using eight protocols, applying a wide variety of laboratory components. Several samples (60% of human specimens) were processed using different protocols. In total, 712 sequencing libraries were investigated for viral sequence contamination.
Among sequences showing similarity to viruses, 493 were significantly associated with the use of laboratory components. Each of these viral sequences had sporadic appearance, only being identified in a subset of the samples treated with the linked laboratory component, and some were not identified in the non-template control samples. Remarkably, more than 65% of all viral sequences identified were within viral clusters linked to the use of laboratory components.
We show that high prevalence of contaminating viral sequences can be expected in HTS-based virome data and provide an extensive list of novel contaminating viral sequences that can be used for evaluation of viral findings in future virome and metagenome studies. Moreover, we show that detection can be problematic due to stochastic appearance and limited non-template controls. Although the exact origin of these viral sequences requires further research, our results support laboratory-component-linked viral sequence contamination of both biological and synthetic origin.
Display omitted
Nonlinear entropy stability and a summation-by-parts framework are used to derive provably stable, polynomial-based spectral collocation element methods of arbitrary order for the compressible ...Navier--Stokes equations. The new methods are similar to strong form, nodal discontinuous Galerkin spectral elements but conserve entropy for the Euler equations and are entropy stable for the Navier--Stokes equations. Shock capturing follows immediately by combining them with a dissipative companion operator via a comparison approach. Smooth and discontinuous test cases are presented that demonstrate their efficacy.
The vital status of patients who are a part of controlled donation after circulatory death (cDCD) is widely debated in bioethical literature. Opponents to currently applied cDCD protocols argue that ...they violate the dead donor rule, while proponents of the protocols advocate compatibility. In this article, we argue that both parties often misinterpret the moral implications of the dead donor rule. The rule as such does not require an assessment of a donor's vital status, we contend, but rather an assessment of whether procurement of organs in cDCD cause the death of the donor or not. We then argue that commonly practiced cDCD protocols do not violate the dead donor rule, since the donation does not trigger or cause the death of the donors.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
PDF
