2,555 research outputs found
Soil CO2 Emissions Associated with Termitaria in Tropical Savanna: Evidence for Hot-Spot Compensation
Our understanding of carbon (C) dynamics within savannas is very limited, especially how source/sink dynamics are influenced by the resident biota. Previous measurements of epigeal termite mounds (termitaria), ubiquitous in many savannas, have shown that they are considerable point sources of soil carbon dioxide (CO2), whereas CO2 measurements collected outside the mounds were generally assumed to be independent of termite activity. However, no measurements were conducted along gradients away from the mounds to confirm this. We quantified daytime soil CO2 emissions (soil respiration) along gradients from the center to 20m from the mound edge in Serengeti National Park, and measured soil temperature/moisture, macro-invertebrate abundance, and vegetation height as variables potentially influencing these emissions. Further, we quantified how far into the savanna termitaria impact CO2 emissions. As in other studies, we found the highest soil CO2 fluxes at the termitaria-center and considerably lower fluxes in the surrounding savanna. Macro-invertebrate abundance was associated with the differences in emissions measured, whereas the other variables were not. The analysis of spatial autocorrelation revealed significantly lower fluxes between the termitaria edge and up to 9m from the edge compared to the values measured at the termitaria-center and between 10 and 20m from the termitaria edge. When extrapolating the emissions across the landscape our results suggest that the lower CO2 emissions found between the edge and 9m fully compensate for the high fluxes measured at the termitaria center. Consequently, our findings provide evidence that termitaria might influence the savanna C source-sink dynamics differently than previously though
Association of smoking and nicotine dependence with pre-diabetes in young and healthy adults.
INTRODUCTION: Several studies have shown an increased risk of type 2 diabetes among smokers. Therefore, the aim of this analysis was to assess the relationship between smoking, cumulative smoking exposure and nicotine dependence with pre-diabetes.
METHODS: We performed a cross-sectional analysis of healthy adults aged 25-41 in the Principality of Liechtenstein. Individuals with known diabetes, Body Mass Index (BMI) >35 kg/m² and prevalent cardiovascular disease were excluded. Smoking behaviour was assessed by self-report. Pre-diabetes was defined as glycosylated haemoglobin between 5.7% and 6.4%. Multivariable logistic regression models were done.
RESULTS: Of the 2142 participants (median age 37 years), 499 (23.3%) had pre-diabetes. There were 1,168 (55%) never smokers, 503 (23%) past smokers and 471 (22%) current smokers, with a prevalence of pre-diabetes of 21.2%, 20.9% and 31.2%, respectively (p <0.0001). In multivariable regression models, current smokers had an odds ratio (OR) of pre-diabetes of 1.82 (95% confidential interval (CI) 1.39; 2.38, p <0.0001). Individuals with a smoking exposure of <5, 5-10 and >10 pack-years had an OR (95% CI) for pre-diabetes of 1.34 (0.90; 2.00), 1.80 (1.07; 3.01) and 2.51 (1.80; 3.59) (p linear trend <0.0001) compared with never smokers. A Fagerström score of 2, 3-5 and >5 among current smokers was associated with an OR (95% CI) for pre-diabetes of 1.27 (0.89; 1.82), 2.15 (1.48; 3.13) and 3.35 (1.73; 6.48) (p linear trend <0.0001).
DISCUSSION: Smoking is strongly associated with pre-diabetes in young adults with a low burden of smoking exposure. Nicotine dependence could be a potential mechanism of this relationship
Complexity of integration, special values, and recent developments
Two questions often come up when the author discusses integration: what is the complexity of the integration process, and for what special values of parameters is an unintegrable function actually integrable. These questions have not been much considered in the formal literature, and where they have been, there is one recent development indicating that the question is more delicate than had been supposed
Load-specific variant generation of bead cross sections in sheet metal components by unidirectional carbon fibre reinforcement
Beads are widely used to stiffen sheet metal components subjected to bending loads.
Often, these bead-stiffened parts are used in product variants that differ significantly in the
amount of acting loads. Lamination of unidirectional carbon fibre reinforced plastic (UD-CFRP)
on the top flange area of individual beads represents a method for further increasing weight-
specific stiffness: By varying the number of plies, a specifically configured component is
obtained for each of the load cases. As a result, no changes to the forming tools are necessary
and a minimum amount of the UD-CFRP material is required. In this work, a complete
manufacturing process for a fibre reinforced bead was developed: First, a bead cross section
geometry with an adapted top flange area to accommodate the UD-CFRP plies was designed
and stamped into pre-stretched sheet samples of DX56 steel. Subsequently, the suitability of
several surface pre-treatment processes to achieve sufficient bond strength of the composite
bead was experimentally investigated and the UD-CFRP plies were applied by lamination. Final
bending tests quantified the achievable stiffening effect of the investigated bead variants,
showing a significant increase of the maximum supportable load compared to the standard non-
reinforced cross-section
A Photometrically and Morphologically Variable Infrared Nebula in L483
We present narrow and broad K-band observations of the Class 0/I source IRAS
18148-0440 that span 17 years. The infrared nebula associated with this
protostar in the L483 dark cloud is both morphologically and photometrically
variable on a time scale of only a few months. This nebula appears to be an
infrared analogue to other well-known optically visible variable nebulae
associated with young stars, such as Hubble's Variable Nebula. Along with
Cepheus A, this is one of the first large variable nebulae to be found that is
only visible in the infrared. The variability of this nebula is most likely due
to changing illumination of the cloud rather than any motion of the structure
in the nebula. Both morphological and photometric changes are observed on a
time scale only a few times longer than the light crossing time of the nebula,
suggesting very rapid intrinsic changes in the illumination of the nebula. Our
narrow-band observations also found that H_2 knots are found nearly twice as
far to the east of the source as to its west, and that H_2 emission extends
farther east of the source than the previously known CO outflow.Comment: 19 pages, 6 figures, 1 tabl
IVDR: Analysis of the Social, Economic, and Practical Consequences of the Application of an Ordinance of the In Vitro Diagnostic Ordinance in Switzerland
IVDR regulation represents a major challenge for diagnostic microbiology laboratories. IVDR complicates a broad range of aspects and poses a risk given the high diversity of pathogens (including rare but highly virulent microbes) and the large variety of samples submitted for analysis. The regular emergence of new pathogens (including Echovirus E-11, Adenovirus 41, Monkeypox virus, Alongshan virus, and Enterovirus D68, as recent examples in Europe in the post SARS-CoV-2 era) is another factor that makes IVDR regulation risky, because its detrimental effect on production of in-house tests will negatively impact knowledge and expertise in the development of new diagnostic tests. Moreover, such regulations negatively impact the availability of diagnostic tests, especially for neglected pathogens, and has a detrimental effect on the overall costs of the tests. The increased regulatory burden of IVDR may thereby pose an important risk for public health. Taken together, it will have a negative impact on the financial balance of diagnostic microbiology laboratories (especially small ones). The already-high standards of quality management of all ISO-accredited and Swissmedic-authorized laboratories render IVDR law of little value, at least in Switzerland, while tremendously increasing the regulatory burden and associated costs. Eventually, patients will need to pay for diagnostic assays outside of the framework of their insurance in order to obtain a proper diagnostic assessment, which may result in social inequity. Thus, based on the risk assessment outlined above, the coordinated commission for clinical microbiology proposes adjusting the IvDO ordinance by (i) introducing an obligation to be ISO 15189 accredited and (ii) not implementing the IvDO 2028 milestone
Label-Free C-Reactive Protein Si Nanowire FET Sensor Arrays With Super-Nernstian Back-Gate Operation
We present a CMOS-compatible double gate and label-free C-reactive protein (CRP) sensor, based on silicon on insulator (SOI) silicon nanowires arrays. We exploit a reference subtracted detection method and a super-Nernstian internal amplification given by the double gate structure. We overcome the Debye screening of charged CRP proteins in solutions using antibodies fragments as capturing probes, reducing the overall thickness of the capture layer. We demonstrate the internal amplification through the pH response of the sensor, in static and real-time working modes. While operated in back-gate configuration, the sensor shows excellent stability (<20 pA/min in the worst case), low hysteresis (<300 mV), and a great sensitivity up to 1.2 nA/dec toward CRP proteins in the linear response range. The reported system is an excellent candidate for the continuous monitoring of inflammation biomarkers in serum or interstitial fluid
DNA transport by a micromachined Brownian ratchet device
We have micromachined a silicon-chip device that transports DNA with a
Brownian ratchet that rectifies the Brownian motion of microscopic particles.
Transport properties for a DNA 50mer agree with theoretical predictions, and
the DNA diffusion constant agrees with previous experiments. This type of
micromachine could provide a generic pump or separation component for DNA or
other charged species as part of a microscale lab-on-a-chip. A device with
reduced feature size could produce a size-based separation of DNA molecules,
with applications including the detection of single nucleotide polymorphisms.Comment: Latex: 8 pages, 4 figure
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