5,287 research outputs found

    Congenital diaphragmatic hernia:A critical appraisal of perinatal care

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    A congenital diaphragmatic hernia (CDH) is a rare birth defect characterised byincomplete closure of the diaphragm. After birth, CDH is associated with significantneonatal morbidity and mortality due to a combination of pulmonary hypoplasia,pulmonary hypertension, and cardiac dysfunction. Despite improvements in clinicalcare, around 30% of these infants do not survive. The research projects reportedin this thesis provide a critical appraisal of important aspects of perinatal care forinfants with CDH.<br/

    Impacts of Global Change and Soil Properties on Phosphorus Transformation and Plant Responses in Alpine Grassland Ecosystem on the Northeastern Tibetan Plateau

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    The grassland ecosystems of the Tibetan Plateau have witnessed substantial transformations in recent decades, driven by various global factors, including alterations in temperature and precipitation, nitrogen (N) deposition, and regional effects. Despite documented shifts in species richness and distribution towards higher elevations, there is a scarcity of comprehensive plant and soil data along elevation gradients in alpine grasslands. The intricate interplay between soil properties and nutrient supply on vegetation patterns at high altitudes, particularly the response of the "grass-line" to global warming, remains unexplored. To bridge these knowledge gaps, our research investigated the impacts of global changes, specifically warming and N deposition, and soil properties on soil phosphorus (P) transformation and plant P uptake. Leveraging insights from long-term nutrient addition experiments, random sampling, and open-top chamber experiments along elevation gradients in an alpine grassland on the northeastern Tibetan Plateau, the study delved into soil properties such as texture, bulk density, soil organic carbon (SOC), and soil P fractions. Furthermore, it explores plant and microbial P pools, P acquisition strategies, and biomass. Results revealed that N input had a discernible effect on plant P requirements, particularly under conditions of deficient soil available P. Changes in P acquisition strategies wielded a more substantial influence on community structure and composition than alterations in root traits. The addition of P significantly impacted plant growth, signifying a shift from nitrogen to P limitation with increased N input. Soil properties exhibited variations among sites, but pH remained stable at 0–10 cm soil depth due to the adequate levels of calcium and magnesium in the soil, which could buffer the impact of N deposition on soil acidification in the grassland ecosystem. Strong positive correlations were observed between organic P pools, SOC, and total N, highlighting the pivotal role of soil organic matter in sustaining soil P reserves. More importantly, P limitation did not emerge as the primary factor propelling grasses to higher elevations; instead, other soil properties and nutrients might play a key role. These findings underscore the importance of specific combinations of soil properties in constraining plant growth on the northeastern plateau, thereby influencing biodiversity and biomass production. This research highlights the factors influencing effective soil nutrients and provides valuable insights into predicting the impact of global changes on the stability and productivity of alpine grassland ecosystems

    Congenital diaphragmatic hernia:A critical appraisal of perinatal care

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    A congenital diaphragmatic hernia (CDH) is a rare birth defect characterised byincomplete closure of the diaphragm. After birth, CDH is associated with significantneonatal morbidity and mortality due to a combination of pulmonary hypoplasia,pulmonary hypertension, and cardiac dysfunction. Despite improvements in clinicalcare, around 30% of these infants do not survive. The research projects reportedin this thesis provide a critical appraisal of important aspects of perinatal care forinfants with CDH.<br/

    Effects of municipal smoke-free ordinances on secondhand smoke exposure in the Republic of Korea

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    ObjectiveTo reduce premature deaths due to secondhand smoke (SHS) exposure among non-smokers, the Republic of Korea (ROK) adopted changes to the National Health Promotion Act, which allowed local governments to enact municipal ordinances to strengthen their authority to designate smoke-free areas and levy penalty fines. In this study, we examined national trends in SHS exposure after the introduction of these municipal ordinances at the city level in 2010.MethodsWe used interrupted time series analysis to assess whether the trends of SHS exposure in the workplace and at home, and the primary cigarette smoking rate changed following the policy adjustment in the national legislation in ROK. Population-standardized data for selected variables were retrieved from a nationally representative survey dataset and used to study the policy action’s effectiveness.ResultsFollowing the change in the legislation, SHS exposure in the workplace reversed course from an increasing (18% per year) trend prior to the introduction of these smoke-free ordinances to a decreasing (−10% per year) trend after adoption and enforcement of these laws (β2 = 0.18, p-value = 0.07; β3 = −0.10, p-value = 0.02). SHS exposure at home (β2 = 0.10, p-value = 0.09; β3 = −0.03, p-value = 0.14) and the primary cigarette smoking rate (β2 = 0.03, p-value = 0.10; β3 = 0.008, p-value = 0.15) showed no significant changes in the sampled period. Although analyses stratified by sex showed that the allowance of municipal ordinances resulted in reduced SHS exposure in the workplace for both males and females, they did not affect the primary cigarette smoking rate as much, especially among females.ConclusionStrengthening the role of local governments by giving them the authority to enact and enforce penalties on SHS exposure violation helped ROK to reduce SHS exposure in the workplace. However, smoking behaviors and related activities seemed to shift to less restrictive areas such as on the streets and in apartment hallways, negating some of the effects due to these ordinances. Future studies should investigate how smoke-free policies beyond public places can further reduce the SHS exposure in ROK

    Spatial Distribution of Meso- and Microplastics in Floodplain Soilscapes: Novel Insights from Rural to Urban Floodplains in Central Germany

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    Plastics and especially microplastics have become an emerging threat to global ecosystems. Despite the manifold benefits and applications of the human-made material plastic, the uncontrolled release of plastics into the environment has led to a “global plastic crisis”. During the last decades it becomes apparent that this crisis leads to the presence of plastics within different environments including marine, aquatic and terrestrial systems under worldwide evidence. Furthermore, environmental plastic research was able to reveal that although plastic often ends up in oceans, the majority of plastics in the environment are transported as part of a “global plastic cycle” from the land to sea via river systems. Those river systems are not isolated in the landscape, but rather a part of an “aquatic-terrestrial interface” which also encompasses floodplains and their soilscapes. The present thesis focuses on the spatial distribution and spatio-temporal accumulation of meso- and microplastics in floodplain soilscapes following the overall objective to unravel the role of floodplain soilscapes as depositional areas of plastics within the global plastic cycle. In this context, a number of individual contributions have been published, reaching from conceptual spatial research approaches, over case studies conducted within two different floodplain soilscapes, to further opinions on the scientific benefit of plastic residues in floodplain soils. The individual contributions are linked by the major hypothesis that floodplain soilscapes act as temporal accumulation sites for plastics, driven by flood-related processes and land use over the last 70 years. To proof this major hypothesis and to overcome the lack of spatial reference in microplastics research, a geospatial sampling approach was conducted. Initial spatial data on meso- and microplastics in floodplain soils were obtained by a holistic analysis approach including the analysis of basic soil feature and metal analysis, the quantification of meso- and microplastics as well as sediment dating. Within both studied river floodplains geospatial sampling enables a detection of meso- and microplastics over the entire floodplain area and within the entire soil column reaching depths of two meters. Additionally, a frequent accumulation of plastics was found within the upper 50 cm of floodplain soils. In combination with dating of near-channel floodplain sites, it could be demonstrated that those plastic accumulations are related to recent sedimentary deposits since the 1960s. However, evidence of plastic from deeper soil layers suggests that vertical displacements in floodplain soils occur and that plastics become mobilized. Furthermore, the presence of plastics in upstream areas suggests that plastics are released to river systems and deposited via flood dynamics already in rural areas. Additionally it appears that anthropogenic impacts, such as tillage or floodplain restoration influence plastic distributions. The findings of this thesis clarify that floodplain soilscapes are part of the global plastic cycle as temporally depositional areas of plastics, but raising further questions on the mobility of plastics in soils and about the exact contribution of different environmental drivers towards plastic deposition. Finally, the present thesis indicates that the spatial reference of environmental plastic research should be rethought, in order to understand the spatial dynamics of plastics within the aquatic-terrestrial interface

    Enhancing the forensic comparison process of common trace materials through the development of practical and systematic methods

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    An ongoing advancement in forensic trace evidence has driven the development of new and objective methods for comparing various materials. While many standard guides have been published for use in trace laboratories, different areas require a more comprehensive understanding of error rates and an urgent need for harmonizing methods of examination and interpretation. Two critical areas are the forensic examination of physical fits and the comparison of spectral data, which depend highly on the examiner’s judgment. The long-term goal of this study is to advance and modernize the comparative process of physical fit examinations and spectral interpretation. This goal is fulfilled through several avenues: 1) improvement of quantitative-based methods for various trace materials, 2) scrutiny of the methods through interlaboratory exercises, and 3) addressing fundamental aspects of the discipline using large experimental datasets, computational algorithms, and statistical analysis. A substantial new body of knowledge has been established by analyzing population sets of nearly 4,000 items representative of casework evidence. First, this research identifies material-specific relevant features for duct tapes and automotive polymers. Then, this study develops reporting templates to facilitate thorough and systematic documentation of an analyst’s decision-making process and minimize risks of bias. It also establishes criteria for utilizing a quantitative edge similarity score (ESS) for tapes and automotive polymers that yield relatively high accuracy (85% to 100%) and, notably, no false positives. Finally, the practicality and performance of the ESS method for duct tape physical fits are evaluated by forensic practitioners through two interlaboratory exercises. Across these studies, accuracy using the ESS method ranges between 95-99%, and again no false positives are reported. The practitioners’ feedback demonstrates the method’s potential to assist in training and improve peer verifications. This research also develops and trains computational algorithms to support analysts making decisions on sample comparisons. The automated algorithms in this research show the potential to provide objective and probabilistic support for determining a physical fit and demonstrate comparative accuracy to the analyst. Furthermore, additional models are developed to extract feature edge information from the systematic comparison templates of tapes and textiles to provide insight into the relative importance of each comparison feature. A decision tree model is developed to assist physical fit examinations of duct tapes and textiles and demonstrates comparative performance to the trained analysts. The computational tools also evaluate the suitability of partial sample comparisons that simulate situations where portions of the item are lost or damaged. Finally, an objective approach to interpreting complex spectral data is presented. A comparison metric consisting of spectral angle contrast ratios (SCAR) is used as a model to assess more than 94 different-source and 20 same-source electrical tape backings. The SCAR metric results in a discrimination power of 96% and demonstrates the capacity to capture information on the variability between different-source samples and the variability within same-source samples. Application of the random-forest model allows for the automatic detection of primary differences between samples. The developed threshold could assist analysts with making decisions on the spectral comparison of chemically similar samples. This research provides the forensic science community with novel approaches to comparing materials commonly seen in forensic laboratories. The outcomes of this study are anticipated to offer forensic practitioners new and accessible tools for incorporation into current workflows to facilitate systematic and objective analysis and interpretation of forensic materials and support analysts’ opinions

    Integral field spectroscopy:a glance to chemo-dynamics in galaxies

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    Abstract. 3D information of the structures in galaxies is not directly available from the morphologies that are, however, needed to target studies on the structures. Alternatively, the spectra of galaxies broadened by the line-of-sight-velocity-distribution (LOSVD) can be used as LOS spatial distribution probes and hold the chemical footprints left along the evolution of galaxies. Knowledge gained from the density distributions and the stellar populations narrows down the processes involved in building these observed morphologies. Integral field spectroscopy (IFS) is an ideal technique for such cases as it instantaneously provides simultaneous morphological and spectral information from the targets. Thick disks and X/B/P bulges are both structures that are often most directly observable in a near edge-on orientation. The vertical density distribution in these structures are the result of evolutional processes that produce stellar populations accordingly but direct information on the distribution vanishes sharply with decreasing inclination (ii) as does our consensus of the structures in the LOS. Investigating such structures and the LOSVDs in simulations can lift some of the doubt and improve our knowledge to be adapted on the search of these structures over various galaxy inclinations. In this thesis Gauss-Hermite series are deployed to scrutinise the LOSVDs in thin-thick disk and X/B/P simulations (A and B) against the IFS data from central regions of 13 (SA-SAB\textrm{SA-S}\underline{\textrm{A}}\textrm{B}) galaxies with M2×1010.5M\langle M_{*}\rangle \approx 2\times10^{10.5}\textrm{M}_{\odot}, T2\langle T \rangle \approx 2, i45°\langle i \rangle \approx 45° from the Spitzer Survey Stellar Structures in Galaxies (S4G\mathrm{S}^{4}\mathrm{G}) sample. Thin-thick disk superposition in simulation-A produces radially increasing amplitudes of the fourth Gauss-Hermite moment (h4h_{4}). The third Gauss-Hermite moment (h3h_{3}) shows mainly anti-correlation with LOSV and persist relatively strong even for low inclinations. These signatures are observed in the IFS data but due to limited field-of-view (FoV) and on-plane rings observed in the systems they are not unambiguous. In simulation-B, negative h4h_{4} minima are found on average at r2hrr \approx 2h_{r} and corresponds to the X-shape structure on edge-on view. Regarding observations, the nuclear region also highlights a h4h_{4}-ring that is a signature observed frequently in the sample. In simulation-B the h4h_{4} ring is produced by the disk-bulge superposition in the LOS and is observable independent of inclination. NGC 1068 and NGC 1387 are found to be X/B/P bulge candidates as both are observed in low ii, in which the fourth vertical density distribution moment (d4d_{4}) is probed by the h4h_{4} moment, and are observed with negative h4h_{4} at a radial distance hr<r<2hrh_{r} \lt r \lt 2h_{r}. In low ii the h4h_{4} minima in simulation-B are found with weak h3Vh_{3}-V correlation that is observed with NGC 1387 but not clearly with NGC 1068.2D spektroskopia : katsaus galaksien kemo-dynamiikkaan. Tiivistelmä. 3D informaatio galaksien rakenteista ei ole suoraan havaittavissa niiden morfologiasta, jota kuitenkin tarvitaan näiden rakenteiden tutkimiseen. Toisaalta galaksien spektrit laajentuessaan katseen suuntaisten nopeusjakaumien (LOSVD) mukaisesti mahdollistavat rakenteiden syvyyssuuntaisen ulottuvuuden tutkimisen ja pitävät sisällään kemialliset jalanjäljet galaksien evoluutiosta. Tiheys/nopeusjakaumista ja tähtipopulaatiosta saatava tieto tuottaa tarkemman kuvan siitä, mitkä prosessit kykenevät muodostamaan galakseissa havaitut rakenteet. 2D-spektroskopia (IFS) on ideaali keino galaksien rakenteiden tutkimiseen sen välittömästi tuottaman yhtäaikaisen morfologisen ja spektroskooppisen informaation ansiosta. Paksukiekot ja X/B/P keskuspullistumat ovat rakenteita, jotka ovat usein havaittavissa suuren inklinaation omaavissa galakseissa. Näiden rakenteiden pystysuuntaiset tiheys/nopeusjakaumat ja tähtipopulaatiot ovat evoluutionaalisten prosessien tulosta, mutta havaittavan galaksin inklinaation ollessa pieni, suora informaatio rakenteiden pystysuuntaisista tiheysjakaumista ja identiteetistä katoaa. Siksi rakenteiden muodon ja niiden katseen suuntaisten nopeushajontojen tutkiminen simulaatiossa vahvistaa käsitystämme galakseissa esiintyvistä rakenteista. Työssä hyödynnetään Gauss-Hermite sarjoja nopeusjakaumien analyysiin kahdessa simulaatiossa ja 2D spektroskopiassa 13:lle (SA-SAB\textrm{SA-S}\underline{\textrm{A}}\textrm{B}) galaksille (M2×1010.5M\langle M_{*}\rangle \approx 2\times10^{10.5}\textrm{M}_{\odot}, T2\langle T \rangle \approx 2, i45°\langle i \rangle \approx 45°) ”Spitzer Survey of Stellar Structures in Galaxies (S4G)” havaintojoukosta. Kaksoiskiekkosimulaatiossa kiekkojen superpositio-LOSVD tuottaa radiaalisesti ulospäin kasvavan Gauss-Hermite sarjan neljännen momentin (h4h_{4}). Gauss-Hermite sarjan kolmas momentti (h3h_{3}) anti-korreloi LOSV kanssa ja on havaittavissa suhteellisen selvästi, myös matalilla simulaatio inklinaatiolla. Vastaavat merkit ovat havaittavissa IFS datasta, mutta rajallisesta havaintoalueesta ja häiriöitä tuottavista rengasrakenteista johtuen ne eivät ole yksiselitteisiä. X/B/P simulaatiossa negatiiviset h4h_{4} minimit esiintyvät keskimäärin etäisyydellä r2hrr \approx 2h_{r}, joka vastaa X-rakennetta kylki-edessä orientaatiossa. Simulaation keskustassa havaitaan keskuspullistuman ja kiekon tuottama h4h_{4} rengas, joka on usein esiintyvä piirre havaintojoukon IFS datassa. NGC 1068 ja NGC 1387 ovat X/B/P keskuspullistuma kandidaatteja, sillä molemmat ovat inklinaatiossa, jossa vertikaalisen tiheysjakauman neljännen momentin (d4d_{4}) tulkinta h4h_{4} arvoista on mahdollista ja molemmissa tapauksissa negatiiviset h4h_{4} minimit löytyvät radiaalisella etäisyydellä hr<r<2hrh_{r} \lt r \lt 2h_{r}. Matalilla inklinaatiolla simulaation h4h_{4} minimit havaitaan heikon h3Vh_{3}-V korrelaation kanssa, joka on havaittavissa NGC 1387:ssä, mutta ei selkeästi NGC 1068:ssa

    Insights into temperature controls on rockfall occurrence and cliff erosion

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    A variety of environmental triggers have been associated with the occurrence of rockfalls however their role and relative significance remains poorly constrained. This is in part due to the lack of concurrent data on rockfall occurrence and cliff face conditions at temporal resolutions that mirror the variability of environmental conditions, and over durations for large enough numbers of rockfall events to be captured. The aim of this thesis is to fill this data gap, and then to specifically focus on the role of temperature in triggering rockfall that this data illuminates. To achieve this, a long-term multiannual 3D rockfall dataset and contemporaneous Infrared Thermography (IRT) monitoring of cliff surface temperatures has been generated. The approaches used in this thesis are undertaken at East Cliff, Whitby, which is a coastal cliff located in North Yorkshire, UK. The monitored section is ~ 200 m wide and ~65 m high, with a total cliff face area of ~9,592 m². A method for the automated quantification of rockfall volumes is used to explore data collected between 2017–2019 and 2021, with the resulting inventory including > 8,300 rockfalls from 2017–2019 and > 4,100 rockfalls in 2021, totalling > 12,400 number of rockfalls. The analysis of the inventory demonstrates that during dry conditions, increases in rockfall frequency are coincident with diurnal surface temperature fluctuations, notably at sunrise, noon and sunset in all seasons, leading to a marked diurnal pattern of rockfall. Statistically significant relationships are observed to link cliff temperature and rockfall, highlighting the response of rock slopes to absolute temperatures and changes in temperature. This research also shows that inclement weather constitutes the dominant control over the annual production of rockfalls but also quantifies the period when temperature controls are dominant. Temperature-controlled rockfall activity is shown to have an important erosional role, particularly in periods of iterative erosion dominated by small size rockfalls. As such, this thesis provides for the first high-resolution evidence of temperature controls on rockfall activity, cliff erosion and landform development

    Mathematical Problems in Rock Mechanics and Rock Engineering

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    With increasing requirements for energy, resources and space, rock engineering projects are being constructed more often and are operated in large-scale environments with complex geology. Meanwhile, rock failures and rock instabilities occur more frequently, and severely threaten the safety and stability of rock engineering projects. It is well-recognized that rock has multi-scale structures and involves multi-scale fracture processes. Meanwhile, rocks are commonly subjected simultaneously to complex static stress and strong dynamic disturbance, providing a hotbed for the occurrence of rock failures. In addition, there are many multi-physics coupling processes in a rock mass. It is still difficult to understand these rock mechanics and characterize rock behavior during complex stress conditions, multi-physics processes, and multi-scale changes. Therefore, our understanding of rock mechanics and the prevention and control of failure and instability in rock engineering needs to be furthered. The primary aim of this Special Issue “Mathematical Problems in Rock Mechanics and Rock Engineering” is to bring together original research discussing innovative efforts regarding in situ observations, laboratory experiments and theoretical, numerical, and big-data-based methods to overcome the mathematical problems related to rock mechanics and rock engineering. It includes 12 manuscripts that illustrate the valuable efforts for addressing mathematical problems in rock mechanics and rock engineering
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