Larix species range dynamics in Siberia since the Last Glacial captured from sedimentary ancient DNA

Climate change is expected to cause major shifts in boreal forests which are in vast areas of Siberia dominated by two species of the deciduous needle tree larch (Larix). The species differ markedly in their ecosystem functions, thus shifts in their respective ranges are of global relevance. However, drivers of species distribution are not well understood, in part because paleoecological data at species level are lacking. This study tracks Larix species distribution in time and space using target enrichment on sedimentary ancient DNA extracts from eight lakes across Siberia. We discovered that Larix sibirica, presently dominating in western Siberia, likely migrated to its northern distribution area only in the Holocene at around 10,000 years before present (ka BP), and had a much wider eastern distribution around 33 ka BP. Samples dated to the Last Glacial Maximum (around 21 ka BP), consistently show genotypes of L. gmelinii. Our results suggest climate as a strong determinant of species distribution in Larix and provide temporal and spatial data for species projection in a changing climate.

Using ancient sedimentary DNA from up to 50 kya, dramatic distributional shifts are documented in two dominant boreal larch species, likely guided by environmental changes suggesting climate as a strong determinant of species distribution.

Organic matter mineralization in modern and ancient ferruginous sediments

Deposition of ferruginous sediment was widespread during the Archaean and Proterozoic Eons, playing an important role in global biogeochemical cycling. Knowledge of organic matter mineralization in such sediment, however, remains mostly conceptual, as modern ferruginous analogs are largely unstudied. Here we show that in sediment of ferruginous Lake Towuti, Indonesia, methanogenesis dominates organic matter mineralization despite highly abundant reactive ferric iron phases like goethite that persist throughout the sediment. Ferric iron can thus be buried over geologic timescales even in the presence of labile organic carbon. Coexistence of ferric iron with millimolar concentrations of methane further demonstrates lack of iron-dependent methane oxidation. With negligible methane oxidation, methane diffuses from the sediment into overlying waters where it can be oxidized with oxygen or escape to the atmosphere. In low-oxygen ferruginous Archaean and Proterozoic oceans, therefore, sedimentary methane production was likely favored with strong potential to influence Earth's early climate.

Fast Starters, Slow Starters, and Late Dippers: Trajectories of Patient-Reported Outcomes After Total Hip Arthroplasty: Results from a Dutch Nationwide Database

BACKGROUND

The purpose of this study was to explore whether subgroups of patients with different functional recovery trajectories after total hip arthroplasty can be discerned, as well as their predictors, using data from the Dutch Arthroplasty Register (Landelijke Registratie Orthopedische Implantaten [LROI]).

METHODS

We retrospectively reviewed prospectively collected Oxford Hip Scores (OHS) up to 1 year postoperatively for patients who had undergone a primary total hip arthroplasty. Latent class growth modeling was used to classify subgroups of patients according to the trajectory of functional recovery represented by the patients' OHS. We used multivariable multinomial logistic regression analysis to explore factors associated with class membership.

RESULTS

A total of 6,030 patients were analyzed. Latent class growth modeling identified fast starters (fast initial improvement, high 12-month scores; 87.7%), slow starters (no initial change and subsequent improvement; 4.6%), and late dippers (initial improvement and subsequent deterioration; 7.7%). Factors associated with slow starters were female sex (odds ratio [OR], 1.63 [95% confidence interval (CI), 1.14 to 2.33]) and smoking (OR, 1.95 [95% CI, 1.26 to 3.03]); an anterior approach (OR, 0.47 [95% CI, 0.29 to 0.78]) had a protective effect against a less favorable response. Factors associated with late dippers were age of >75 years (OR, 1.62 [95% CI, 1.22 to 2.15]), smoking (OR, 1.68 [95% CI, 1.17 to 2.42]), American Society of Anesthesiologists (ASA) grade of III or IV (OR, 1.41 [95% CI, 1.05 to 1.91]), obesity (OR, 1.96 [95% CI, 1.43 to 2.69]), poorer EuroQol-5 Dimensions (EQ-5D) Self-Care (OR, 1.41 [95% CI, 1.09 to 1.82] for "some problems" and OR, 2.90 [95% CI, 1.39 to 6.03] for "unable"), poorer EQ-5D Anxiety/Depression (OR, 1.31 [95% CI, 1.00 to 1.71] for "moderately" and OR, 1.86 [95% CI, 1.06 to 3.24] for "extremely"), poorer EQ-5D visual analog scale (OR, 0.91 [95% CI, 0.86 to 0.97] per 10 points), direct lateral approach (OR, 2.18 [95% CI, 1.58 to 3.02]), and hybrid fixation with a cemented acetabular implant (OR, 1.79 [95% CI, 1.00 to 3.21]).

CONCLUSIONS

We discerned fast starters, slow starters, and late dippers after total hip arthroplasty. Female sex, older age, obesity, higher ASA grades, and worse EQ-5D scores were associated with a less favorable response to total hip arthroplasty, as well as hybrid fixation (cemented acetabular implant) and direct lateral approach. Anterior approach had a protective effect against a less favorable response. However, all subgroups experienced functional improvement following total hip arthroplasty.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Mediterranean winter rainfall in phase with African monsoons during the past 1.36 million years

Mediterranean climates are characterized by strong seasonal contrasts between dry summers and wet winters. Changes in winter rainfall are critical for regional socioeconomic development, but are difficult to simulate accurately¹ and reconstruct on Quaternary timescales. This is partly because regional hydroclimate records that cover multiple glacial-interglacial cycles^2,3 with different orbital geometries, global ice volume and atmospheric greenhouse gas concentrations are scarce. Moreover, the underlying mechanisms of change and their persistence remain unexplored. Here we show that, over the past 1.36 million years, wet winters in the northcentral Mediterranean tend to occur with high contrasts in local, seasonal insolation and a vigorous African summer monsoon. Our proxy time series from Lake Ohrid on the Balkan Peninsula, together with a 784,000-year transient climate model hindcast, suggest that increased sea surface temperatures amplify local cyclone development and refuel North Atlantic low-pressure systems that enter the Mediterranean during phases of low continental ice volume and high concentrations of atmospheric greenhouse gases. A comparison with modern reanalysis data shows that current drivers of the amount of rainfall in the Mediterranean share some similarities to those that drive the reconstructed increases in precipitation. Our data cover multiple insolation maxima and are therefore an important benchmark for testing climate model performance.

Dynamics of an orthopaedic team: Insights to improve teamwork through a design thinking approach

BACKGROUND:

Supporting teamwork in healthcare is a way to foster both the quality and safety of care, and better working conditions for all the team members. Although increasing attention is paid to this topic on a general level, there is less knowledge about its unfolding in orthopaedic units and its translation to interventions.

OBJECTIVE:

To identify concrete opportunities for teamwork intervention through a design thinking approach by analysing the teamwork dynamics of an orthopaedic team.

METHODS:

An adaptation of the learning history method, comprising shadowing, observations and interviews involving 26 orthopaedic team members at a top clinical teaching hospital in the Netherlands, was applied. A thematic analysis was conducted to derive themes that describe team dynamics and to subsequently extrapolate opportunities for intervention.

RESULTS:

We identified five themes and translated them into four design opportunities for intervention, namely: a) Improve daily rounds by reducing cognitive overload and promoting confidence; b) Improve collaboration by building empathy; c) Connect the patient with the professional team; and d) Support changes by fostering learning. Suggestions for concrete actions are presented for each opportunity.

CONCLUSIONS:

Opportunities to improve teamwork among healthcare professionals, specifically those in orthopaedics, revolve around the creation of common knowledge, the fostering of mutual understanding, and the design of tools and activities that support these processes.

Supporting the scholar role in intensive care nursing

This study investigates how future informatics applications can support and challenge intensive care nurses (ICU nurses) to grow and learn continuously. To this end a research-and-design tool is introduced which is based on a model of the nursing process that starts from the idea that a nurse fulfills three different roles: the role of practitioner (using information immediately to base actions upon), the role of scholar (using information later on to learn from) and the role of human (coping with stress and dealing with emotions). In this paper the focus is on the scholar role. Twenty-eight intensive care staff members from six different hospitals were asked to recount an imposing experience from the perspective of each role. Regarding the scholar role, the participants mentioned 77 learning strategies they adopt for individual as well as organizational learning. Individual learning concerned reflection on former patient cases, reflection on current patient cases to anticipate a change in the patient's condition and reflection on personal behavior and decisions. Organizational learning concerned reflection on former patient cases. Examples of specific strategies were formal team evaluations focused on procedure and understanding the perspective of team members, being present at autopsies, and giving feedback on the nursing skills of colleagues. Based on these strategies design implications are defined for future nursing informatics applications, which will be presented.

El'gygytgyn impact crater, Chukotka, Arctic Russia: Impact cratering aspects of the 2009 ICDP drilling project

The El'gygytgyn impact structure in Chukutka, Arctic Russia, is the only impact crater currently known on Earth that was formed in mostly acid volcanic rocks (mainly of rhyolitic, with some andesitic and dacitic, compositions). In addition, because of its depth, it has provided an excellent sediment trap that records paleoclimatic information for the 3.6 Myr since its formation. For these two main reasons, because of the importance for impact and paleoclimate research, El'gygytgyn was the subject of an International Continental Scientific Drilling Program (ICDP) drilling project in 2009. During this project, which, due to its logistical and financial challenges, took almost a decade to come to fruition, a total of 642.3 m of drill core was recovered at two sites, from four holes. The obtained material included sedimentary and impactite rocks. In terms of impactites, which were recovered from 316.08 to 517.30 m depth below lake bottom (mblb), three main parts of that core segment were identified: from 316 to 390 mblb polymict lithic impact breccia, mostly suevite, with volcanic and impact melt clasts that locally contain shocked minerals, in a fine-grained clastic matrix; from 385 to 423 mblb, a brecciated sequence of volcanic rocks including both felsic and mafic (basalt) members; and from 423 to 517 mblb, a greenish rhyodacitic ignimbrite (mostly monomict breccia). The uppermost impactite (316-328 mblb) contains lacustrine sediment mixed with impact-affected components. Over the whole length of the impactite core, the abundance of shock features decreases rapidly from the top to the bottom of the studied core section. The distinction between original volcanic melt fragments and those that formed later as the result of the impact event posed major problems in the study of these rocks. The sequence that contains fairly unambiguous evidence of impact melt (which is not very abundant anyway, usually less than a few volume%) is only about 75 m thick. The reason for this rather thin fallback impactite sequence may be the location of the drill core on an elevated part of the central uplift. A general lack of large coherent melt bodies is evident, similar to that found at the similarly sized Bosumtwi impact crater in Ghana that, however, was formed in a target composed of a thin layer of sediment above crystalline rocks.

Pliocene warmth, polar amplification, and stepped Pleistocene cooling recorded in NE Arctic Russia

Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, in northeast (NE) Arctic Russia, shows that 3.6 to 3.4 million years ago, summer temperatures were ~8°C warmer than today, when the partial pressure of CO2 was ~400 parts per million. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until ~2.2 million years ago, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene.

Holocene climate changes reflected in a diatom succession from Basaltsø, East Greenland

Information on Holocene lacustrine diatom records from Greenland is rare. Here, a complete Holocene diatom succession is described from a sediment core recovered from Basaltsø, an arctic lake on Geographical Society Ø, eastern Greenland. Based on radiocarbon measurements on plant material, the upper 2.42 m of the 9.85 m long sediment sequence represent the Holocene sedimentological record in this area from about 10 000 calibrated (cal.) years BP. The diatom assemblages in Basaltsø are dominated by only a few species. Four stratigraphic diatom zones could be distinguished. During the early Holocene, mainly Staurosira construens (Ehr.) Williams et Round, Nitzschia amphibia Grunow, and Pinnularia mesolepta (Ehr.) W. Smith were the dominant taxa. After this initial stage, between 9600 and 5000 cal. years BP, Staurosirella pinnata (Ehr.) Williams et Round was the most abundant diatom species. From 4500 to 500 cal. years BP, the diatom assemblage was characterized by the co-occurrence of several taxa, including S. construens. S. pinnata, Kolbesia suchlandtii (Hust.) Kingston, and Cyclotella sp. A (rossii–tripartita–comensis complex) as the main contributors. Finally, from 500 cal. years BP, the diatom assemblage was clearly dominated by Cyclotella sp. A, Cyclotella pseudostelligera Hustedt, and Sellaphora spp. The Holocene relative frequencies of S. pinnata and S. construens clearly correlate with the total diatom valve concentration, the Betula and Salix pollen percentage in Basaltsø, and the oxygen isotope record from the Renland ice core. This suggests that S. pinnata and S. construens are temperature-sensitive species that responded on the general climatic development in eastern Greenland during the Holocene. The diatom record together with the pollen and geochemical data of Basaltsø indicate to the Holocene climatic optimum on Geographical Society Ø from ca. 9000 to 6500 cal. years BP.Key words: Arctic, Greenland, Holocene, diatoms, paleolimnology, environmental change.