A comparison of different inverse carbon flux estimation approaches for application on a regional domain

We have implemented six different inverse carbon flux estimation methods in a regional carbon dioxide (CO<sub>2</sub>) flux modeling system for the Netherlands. The system consists of the Regional Atmospheric Mesoscale Modeling System (RAMS) coupled to a simple carbon flux scheme which is run in a coupled fashion on relatively high resolution (10 km). Using an Ensemble Kalman filter approach we try to estimate spatiotemporal carbon exchange patterns from atmospheric CO<sub>2</sub> mole fractions over the Netherlands for a two week period in spring 2008. The focus of this work is the different strategies that can be employed to turn first-guess fluxes into optimal ones, which is known as a fundamental design choice that can affect the outcome of an inversion significantly. <br><br> Different state-of-the-art approaches with respect to the estimation of net ecosystem exchange (NEE) are compared quantitatively: (1) where NEE is scaled by one linear multiplication factor per land-use type, (2) where the same is done for photosynthesis (GPP) and respiration (<i>R</i>) separately with varying assumptions for the correlation structure, (3) where we solve for those same multiplication factors but now for each grid box, and (4) where we optimize physical parameters of the underlying biosphere model for each land-use type. The pattern to be retrieved in this pseudo-data experiment is different in nearly all aspects from the first-guess fluxes, including the structure of the underlying flux model, reflecting the difference between the modeled fluxes and the fluxes in the real world. This makes our study a stringent test of the performance of these methods, which are currently widely used in carbon cycle inverse studies. <br><br> Our results show that all methods struggle to retrieve the spatiotemporal NEE distribution, and none of them succeeds in finding accurate domain averaged NEE with correct spatial and temporal behavior. The main cause is the difference between the structures of the first-guess and true CO<sub>2</sub> flux models used. Most methods display overconfidence in their estimate as a result. A commonly used daytime-only sampling scheme in the transport model leads to compensating biases in separate GPP and <i>R</i> scaling factors that are readily visible in the nighttime mixing ratio predictions of these systems. <br><br> Overall, we recommend that the estimate of NEE scaling factors should not be used in this regional setup, while estimating bias factors for GPP and <i>R</i> for every grid box works relatively well. The biosphere parameter inversion performs good compared to the other inversions at simultaneously producing space and time patterns of fluxes and CO<sub>2</sub> mixing ratios, but non-linearity may significantly reduce the information content in the inversion if true parameter values are far from the prior estimate. Our results suggest that a carefully designed biosphere model parameter inversion or a pixel inversion of the respiration and GPP multiplication factors are from the tested inversions the most promising tools to optimize spatiotemporal patterns of NEE

Modelling representation errors of atmospheric CO2 mixing ratios at a regional scale

Inverse modelling of carbon sources and sinks requires an accurate quality estimate of the modelling framework to obtain a realistic estimate of the inferred fluxes and their uncertainties. So-called "representation errors" result from our inability to correctly represent point observations with simulated average values of model grid cells. They may add substantial uncertainty to the interpretation of atmospheric CO2 mixing ratio data. We simulated detailed variations in the CO2 mixing ratios with a high resolution (2 km) mesoscale model (RAMS) to estimate the representation errors introduced at larger model grid sizes of 10 100 km. We found that meteorology is the main driver of representation errors in our study causing spatial and temporal variations in the error estimate. Within the nocturnal boundary layer, the representation errors are relatively large and mainly caused by unresolved topography at lower model resolutions. During the day, convective structures, mesoscale circulations, and surface CO2 flux variability were found to be the main sources of representation errors. Interpreting observations near a mesoscale circulation as representative for air with the correct footprint relative to the front can reduce the representation error substantially. The remaining representation error is 0.5 1.5 ppm at 20 100 km resolution

Natural age dispersion arising from the analysis of broken crystals, part II. Practical application to apatite (U-Th)/He thermochronometry

We describe a new numerical inversion approach to deriving thermal history information from a range of naturally dispersed single grain apatite (U-Th)/He ages. The approach explicitly exploits the information about the shape of the 4He diffusion profile within individual grains that is inherent in the pattern of dispersion that arises from the common and routine practice of analysing broken crystals. Additional dispersion arising from differences in grain size and in U and Th concentration of grains, and the resultant changes to helium diffusivity caused by differential accumulation and annealing of radiation damage, is explicitly included. In this approach we calculate the ingrowth and loss, due to both thermal diffusion and the effects of α-ejection, of helium over time using a finite cylinder geometry. Broken grains are treated explicitly as fragments of an initially larger crystal. The initial grain lengths, L0, can be treated as unknown parameters to be estimated, although this is computationally demanding. A practical solution to the problem of solving for the unknown initial grain lengths is to simply apply a constant and sufficiently long L0 value to each fragment. We found that a good value for L0 was given by the maximum fragment length plus two times the maximum radius of a given set of fragments. Currently whole crystals and fragments with one termination are taken into account. A set of numerical experiments using synthetic fragment ages generated for increasingly complex thermal histories, and including realistic amounts of random noise (5-15%), are presented and show that useful thermal history information can be extracted from datasets showing very large dispersion. These include experiments where dispersion arises only from fragmentation of a single grain (length 400μm and radius 75μm, c. 6-50% dispersion), including the effects of grain size variation (for spherical equivalent grain radii between 74-122 μm, c. 10-70% dispersion) and the combined effects of fragmentation, grain size and radiation damage (for eU between 5-150 ppm, c.10-107% dispersion). Additionally we show that if the spherical equivalent radius of a broken grain is used as a measure of the effective diffusion domain for thermal history inversions then this will likely lead to erroneous thermal histories being obtained in many cases. The viability of the new technique is demonstrated for a real data set of 25 single grain (U-Th)/He apatite ages obtained for a gabbro sample from the BK-1 (Bierkraal) borehole drilled through the Bushveld Complex in South Africa. The inversion produces a well constrained thermal history consistent with both the (U-Th)/He data and available fission track analysis data. The advantage of the new approach is that it can explicitly accommodate all the details of conventional schemes, such as the effects of temporally variable diffusivity, zonation of U and Th and arbitrary grain size variations, and it works equally effectively for whole or broken crystals, and for the most common situation where a mixture of both are analysed. For the routine application of the apatite (U-Th)/He thermochronometry technique with samples where whole apatite grains are rare our experiments indicate that 15-20 single grain analyses are typically required to characterise the age dispersion pattern of a sample. The experiments also suggest that picking very short crystal fragments as well as long fragments, or even deliberately breaking long crystals to maximise the age dispersion in some cases, would ensure the best constraints on the thermal history models. The inversion strategy described in this paper is likely also directly applicable to other thermochronometers, such as the apatite, rutile and titanite U-Pb systems, where the diffusion domain is approximated by the physical grain size

Междисциплинарные проблемы аддитивных технологий: сборник тезисов III Всероссийского научного семинара с международным участием, 4-6 декабря 2017, Томск

Этот сборник включает тезисы устных и стендовых докладов III Всероссийского научного семинара с международным участием «Междисциплинарные проблемы аддитивных технологий». Семинар организован для содействия обмену результатами и опытом в области научных исследований, связанных с аддитивными технологиями, в целях развития и усиления интеграции упомянутых ранее исследований. Программа семинара в 2017 году охватывает проблемы материаловедения в аддитивных технологиях

Küçük bir devr-i âlem

H. A.'nın Çocuklara Rehber'de tefrika edilen Küçük Bir Devr-i Âlem adlı roman

Project of motion capture system based on free layout of sensors on the modeled object

The article presents the review of motion capture systems based on different physical principles and used in different areas of human activity. There is a description of cheap system that can be used instead of foreign analogs. It is based on 9-axis motion capture devices and could allow to place these devices on different kind of objects

Chronotype changes with age; seven-year follow-up from the Netherlands study of depression and anxiety cohort

Background: Chronotype reflects an individual's optimal daily timing of sleep, activity, and cognitive performance. Previous, cross-sectional, studies have suggested an age effect on chronotype with later chronotypes in adolescents and earlier chronotypes in children and elderly. Additionally, later chronotypes have been associated with more depressive symptoms. Few studies have been able to study longitudinal associations between chronotype and age, while adjusting for depressive symptoms. Methods: Chronotype was assessed twice with the Munich Chronotype Questionnaire 7 years apart in the Netherlands Study of Depression and Anxiety (T1: N = 1842, mean age (SD): 42.63 years (12.66)) and T2: N = 1829, mean age (SD) 50.67 (13.11)). The longitudinal association between change in age and change in chronotype was tested using a generalized estimated equation analysis adjusted for covariates (including level of depressive symptoms). Using age-bins of 5 years (age at T2), change in chronotype between T1 and T2 was analyzed with Linear Mixed Models. Results: We found a change towards an earlier chronotype with higher age (B (95% CI): -0.011 (-0.014-0.008), p < 0.001). For the age-bins, the difference in chronotype was significant for the 25-29 years age-bin. Limitations: The sample did not include individuals younger than 19 years or older than 68 years. Conclusions: In the whole sample chronotype changed towards becoming more morning-type over a period of 7 years, but this change was only significant for those aged 25-29 years. The study was performed in a large naturalistic cohort study with a wide age-range, including patients with a diagnosis of depressive and anxiety disorder and healthy controls.Stress and Psychopatholog

The effects of pelvic ring injuries on quality of life, physical, and mental health:results of a 2-year prospective cohort study

PURPOSE: Pelvic ring injuries are known to affect the patients' daily life in terms of physical functioning and quality of life (QoL). Still, prospective studies on the patient's perception over the first 2 years of rehabilitation are lacking. Therefore, patients cannot be properly informed about whether or when they will return to their pre-existing level of physical functioning and QoL. METHODS: A prospective longitudinal cohort study was performed over a 4-year period including all consecutive patients above 18 years who sustained a pelvic ring injury in a level 1 trauma center. Validated patient-reported outcome measures (PROMs) were used to assess physical functioning (SMFA) and QoL (EQ-5D) at baseline (recalled pre-injury score), 6 weeks, 3 months, 6 months, 1 year and 2 years after the injury. It was assessed whether patients had fully recovered by comparing follow-up scores to baseline PROMs. Binary logistic regression analysis was used to identify independent predictors for patients who did not fully recover. Most experienced difficulties at 3 months and 1 year were identified by analyzing the highest reported scores on individual items of the SMFA. RESULTS: A total of 297 patients with a pelvic ring injury were identified of which 189 were eligible for follow-up and 154 (82%) responded. Median SMFA function score at 3 months, 1 and 2 years was 70, 78 and 88, respectively, compared to 96 out of 100 before the injury. Median SMFA bother score was 67, 79 and 88, respectively. Median EQ-5D score at 3 months, 1 and 2 years was 0.61, 0.81 and 0.85, respectively, compared to 1 (maximum achievable) before the injury. After 1 and 2 years of follow-up, 61% and 75% of the patients fully "recovered" in physical functioning and 52% and 71% fully recovered in terms of QoL. Female gender and high-energy trauma were independent predictors for not fully recovering after 1 year. After 3 months of follow-up, 54% of patients reported severe difficulties with recreational activities, whereas after 1 year, most experienced difficulties (31% of patients) concerned heavy house or yard work. Moreover, after 3 months and 1 year, 44% and 27% of patients reported feeling physically disabled. CONCLUSION: Pelvic ring injuries have a large impact on the patients' daily life in the first 2 years of rehabilitation. Directly after the injury, physical functioning and QoL decrease strongly but then gradually improve over a 2-year period with about 75% of patients fully recovering. Female gender and high-energy trauma are shown to be independent predictors for not fully recovering. After 3 months, patients experience difficulties with both the physical and mental effects of the injury which continue to be present after 1 year

Разработка алгоритмического и программного обеспечение для передачи данных в сетях MANET

Объектом исследования являются алгоритмы маршрутизации, проектирование алгоритмов маршрутизации для сети с использованием технологии Wi-Fi Direct, программная реализация спроектированных алгоритмов маршрутизации. Цель работы – спроектировать алгоритмы маршрутизации для сетей построенных с помощью технологии Wi-Fi Direct и реализовать спроектированные алгоритмы. В результате проектирования были получены следующие алгоритмы: алгоритм поиска маршрута, алгоритм передачи данных, алгоритм фрагментации данных. В результате реализации было разработано мобильное приложение, которое передает данные, используя технологию Wi-Fi Direct. Были реализованы алгоритм поиска маршрута и алгоритм передачи данных.The object of the study are routing algorithms, design of routing algorithms for the network using Wi-Fi Direct technology, software implementation of the designed routing algorithms. The aim of the work is to design routing algorithms for networks built using Wi-Fi Direct technology and implement the designed algorithms. As a result of the design, the following algorithms were obtained: the route search algorithm, the data transfer algorithm, and the data fragmentation algorithm. As a result of the implementation, a mobile application was developed that transmits data using Wi-Fi Direct technology. The algorithm of the route search and the data transfer algorithm were implemented