Comparing Quantitative Methods for Analyzing Sediment DNA Records of Cyanobacteria in Experimental and Reference Lakes

Sediment DNA (sedDNA) analyses are rapidly emerging as powerful tools for the reconstruction of environmental and evolutionary change. While there are an increasing number of studies using molecular genetic approaches to track changes over time, few studies have compared the coherence between quantitative polymerase chain reaction (PCR) methods and metabarcoding techniques. Primer specificity, bioinformatic analyses, and PCR inhibitors in sediments could affect the quantitative data obtained from these approaches. We compared the performance of droplet digital polymerase chain reaction (ddPCR) and high-throughput sequencing (HTS) for the quantification of target genes of cyanobacteria in lake sediments and tested whether the two techniques similarly reveal expected patterns through time. Absolute concentrations of cyanobacterial 16S rRNA genes were compared between ddPCR and HTS using dated sediment cores collected from two experimental (Lake 227, fertilized since 1969 and Lake 223, acidified from 1976 to 1983) and two reference lakes (Lakes 224 and 442) in the Experimental Lakes Area (ELA), Canada. Relative abundances of Microcystis 16S rRNA (MICR) genes were also compared between the two methods. Moderate to strong positive correlations were found between the molecular approaches among all four cores but results from ddPCR were more consistent with the known history of lake manipulations. A 100-fold increase in ddPCR estimates of cyanobacterial gene abundance beginning in ~1968 occurred in Lake 227, in keeping with experimental addition of nutrients and increase in planktonic cyanobacteria. In contrast, no significant rise in cyanobacterial abundance associated with lake fertilization was observed with HTS. Relative abundances of Microcystis between the two techniques showed moderate to strong levels of coherence in top intervals of the sediment cores. Both ddPCR and HTS approaches are suitable for sedDNA analysis, but studies aiming to quantify absolute abundances from complex environments should consider using ddPCR due to its high tolerance to PCR inhibitors

Logistik: Hur påverkar Just-In-Time på lönsamheten av ett företag?

Ett företag har som grunduppgift att hållas verksamt genom att ekonomiskt prestera bättre för varje år. Logistik är det verksamhetsområde som står för majoriteten av ett företags kostnader. Kostnader i sig är en dålig sak för företag, men det är även en möjlighet för logistiken att sänka dessa kostnader, vilket i sin tur är bra för företagets lön-samhet. Just-In-Time (JIT) är en produktions- och styrfilosofi inom logistiken, där det huvudsakliga målet är att minska lagernivåerna och att eliminera allt onödigt. Syftet med denna studie är att finna ett samband mellan JIT och lönsamhet ur ett logistiskt perspektiv. Vid studien används DuPont-modellen som definition av lönsamhet samt som ett jämförelseverktyg där sex olika finansiella faktorer mäts. Metoden för studien är kvalitativ i form av en litteraturstudie. Materialet som analyseras hämtas endast från Arcadas databaser och analysen av materialet sker i form av innehållsanalys. Resultaten av materialet som analyserades är väldigt blandat. Många studier påpekar att det råder brist på forskning inom detta ämnesområdet, vilket även kan vara orsaken till dessa blandade resultat. Det går dock att urskilja tre finansiella mått från DuPont-modellen som påver-kas positivt av JIT. Dessa är: intäkter, kostnader och lager. Ingen studie visade att JIT skulle ha negativ inverkan på ett företags lönsamhet. Andra intressanta faktorer som JIT hade en positiv inverkan på är operativa prestanda, t.ex. minskade ledtider

Postnatal Growth after Intrauterine Growth Restriction Alters Central Leptin Signal and Energy Homeostasis

Intrauterine growth restriction (IUGR) is closely linked with metabolic diseases, appetite disorders and obesity at adulthood. Leptin, a major adipokine secreted by adipose tissue, circulates in direct proportion to body fat stores, enters the brain and regulates food intake and energy expenditure. Deficient leptin neuronal signalling favours weight gain by affecting central homeostatic circuitry. The aim of this study was to determine if leptin resistance was programmed by perinatal nutritional environment and to decipher potential cellular mechanisms underneath

Prise en charge des pertes de substance osseuse du membre inférieur par la technique chirurgicale de la Membrane Induite

La technique chirurgicale de la membrane induite décrite par Masquelet semble offrir une solution thérapeutique efficace dans la gestion des larges pertes de substance osseuse du membre inférieur chez l’adulte, avec des taux de consolidation satisfaisants, malgré de nombreuses complications post-opératoires, en particulier infectieuses. Notre étude a permis de démontrer son efficacité aussi bien dans la prise en charge des fractures que dans la gestion des pseudarthroses diaphysaires du tibia ou du fémur. Il semblerait que cette intervention soit plus efficace en termes de délai de consolidation au niveau du fémur qu’au niveau du tibia.A l’heure actuelle, de nombreuses questions restent en suspens. Existe-t-il une technique chirurgicale plus efficace que la technique chirurgicale de la membrane induite décrite par Masquelet ? Comme nous l’avons vu précédemment, cette intervention semble moins efficace au niveau du tibia (délai de consolidation plus long qu’au niveau du fémur). Dans ce cas-là, qu’elle est la place des autres techniques chirurgicale comme celle d’Ilizarov et du transport osseux, plus ou moins associée à un enclouage centromédullaire ? Quelle est la meilleure greffe osseuse et quelle est la place des substituts osseux et des substances ostéogéniques dans la technique chirurgicale de la membrane induite ? La tendance actuelle, nous oriente vers des greffes combinées (autogreffe osseuse, allogreffe morcelée, substitut osseux et facteurs de croissance) permettant de répondre aux conditions requises par le « Diamond concept ». Toutes ces questions ouvrent la voie à de nombreuses recherches pour optimiser la prise en charge des larges pertes de substance osseuse

L’entraide internationale en matière pénale et les entreprises : analyses de lege lata et réflexions de lege ferenda

En 2003, lorsque l’entreprise a fait sa grande entrée dans le droit pénal suisse, il n’a pas été question de modifier le droit de l’entraide qui, pourtant, ne la prévoyait pas. L’introduction de ce nouvel acteur pénal n’a pas été sans poser diverses problématiques, ne serait-ce que dans une première mesure ce qu’englobe exactement le terme d’entreprise. De surcroît, si l’on peut attribuer, d’une façon générale, à l’être humain, la conscience de ses actions et la faculté physique de modifier son environnement, il est moins clair que l’entité immatérielle qu’est l’entreprise puisse être capable de commettre des actes, puis d’en être tenue pour responsable. Dès lors que les responsabilités des entités collectives se sont développées mondialement, la coopération internationale a dû s’adapter à cet auteur particulier. Pourtant, aucune modification législative n’a été proposée concernant la loi sur l'entraide internationale en matière pénale (EIMP), qui n’est pas sans contenir des conditions ne favorisant pas toujours la coopération. Nous pouvons alors nous demander, tout d’abord, dans quelle mesure le droit actuel suisse de la coopération internationale en matière pénale peut-il être appliqué aux procédures visant des personnes morales ? Ensuite, quelles modifications seraient adéquates ou nécessaires pour harmoniser la responsabilité pénale de l’entreprise au droit de la coopération

Preface

International audienc

Comparing the outcomes of the induced membrane technique between the tibia and femur: Retrospective single-center study of 33 patients

International audienceIntroduction: Bone defects are challenging to treat surgically. The primary objective of our study was to compare the union rate and time to union between the tibia and femur when using the induced membrane technique. The secondary objective was to document how failures were managed.Material and Methods: This retrospective, single-center study involved 33 patients (23 men, 10 women) who were older than 18 years of age. They were treated surgically for a leg fracture or long bone nonunion (22 tibia, 11 femur) using the induced membrane technique between January 2011 and December 2016 and had a complete follow-up. The minimum follow-up was 1 year for fractures and 2 years for non-union cases. Bone union was defined as the presence of at least two cortices with bridging on two radiographic views and return to full weight bearing.Results: The mean patient age was 38.3 ± 15.5 years (18-72). The mean bone defect size was 7.9 ± 5.0 cm (2.3-18.0). The mean follow-up was 3.3 ± 1.8 years (1-7.2). The union rate was 61% (20 patients). The mean time to union was 10 ± 6.4 months (3-23). The time to union was significantly longer in the tibia (11.6 ± 6.9 months [3-23]) than in the femur (6.3 ± 2.9 months [3.4-10.3]) (p = 0.025). The failure rate did not differ between the tibia and femur. Nine of the 13 patients (69%) in which the treatment failed were reoperated; 7 of them underwent nonunion treatment (78%) and 2 underwent amputation (22%). The other 4 patients were waiting for an infection to resolve before being reoperated.Conclusion: The induced membrane technique is an effective surgical procedure for large bone defects in both the tibia and femur. However, the time to union was shorter in the femur than the tibia in our cohort

Global acceleration of lake sediment accumulation rates associated with recent human population growth and land-use changes

Sediment Accumulation Rate (SAR; measured as mm yr(-1)) and Mass Accumulation Rate (MAR; measured as g cm(-2) yr(-1)) data were collected from published lake core records that spanned the past similar to 150 years, from approximately 500 sites worldwide. For each lake, key watershed characteristics including watershed size, slope, land use and climate were extracted, with the goal of quantifying the relative importance of these variables as drivers of SAR and MAR. General additive models provided evidence of accelerated global lake sediment infilling rates after AD 1950. Whereas the onset of sedimentation acceleration varied across ecoregions, global lake MAR values were found to have increased similar to threefold on average, since baseline conditions pre-1900 (i.e. mu(baseline) = 0.040 +/- 0.044 g cm(-2) yr(-1) and mu(modern) = 0.13 +/- 0.22 g cm(-2) yr(-1)). The significant drivers, identified through Linear Mixed Effect modeling of MAR time series, were watershed population density (log-transformed) and watershed cropland density (log-transformed). Our results highlight important spatial heterogeneity in SAR and MAR among lakes, precluding the use of simple modeling approaches. SAR and MAR were found to be moderately correlated to one another, despite the potential for post-depositional disparities between segments of the sediment cores. We identified organic matter content (loss-on-ignition, LOI) as a significant co-variate that could be used to correct inflated very recent SAR rates. Our empirical analyses suggest that, despite a wide range of natural variability among lakes, both SAR and MAR increased globally and the increases appear to be mainly the result of enhanced watershed activities associated with agriculture and urbanization

A pan-Canadian calibration of micro-X-ray fluorescence core scanning data for prediction of sediment elemental concentrations

Sediment geochemistry is one lens through which lake sediments are studied to reconstruct local and regional environmental processes. The measurement of sediment elemental composition has historically relied on expensive and destructive methods that limit the spatial and temporal scale of study. Micro-X-ray fluorescence (µXRF) core scanning offers a non-destructive, high-resolution alternative, but its results (i.e., intensity expressed as counts per second) are considered semi-quantitative and comparison among sites requires calibration. Calibration methods are emerging, although they are not yet widely employed and require further assessment of their efficacy. Using 135 sediment samples from 48 lakes across Canada, we assessed the congruence between µXRF and conventionally measured element compositions with various normalization and calibration techniques. Normalization of µXRF data to common proxies (e.g., Ca, Si, Ti, coherence:incoherence ratio, and total counts per second) often improved correlations between µXRF and conventional data, but increases were modest and not consistent for all elements. Our results suggest that µXRF normalization techniques should be applied cautiously, as no proxy represents a “one-size-fits-all” solution. The performance of multivariate log-ratio calibration (MLC) was more consistent, yielding moderate to strong improvement of the correlations between reference and predicted element concentrations. Random forest regression models outperformed partial least squares regression models for almost all elements. MLC may be applied where knowledge of elemental concentration is of great importance, or when comparing across multiple sites with diverse sediment geochemistries. Overall, our results reinforce uncalibrated µXRF core scanning as a strong investigative tool for measuring sediment geochemistry. Although calibrated µXRF data shows promise, conventional methods for measuring sediment geochemistry are still necessary for comparing element concentrations with sediment quality guidelines