52 research outputs found

    High-Resolution Nonlinear Raman Spectroscopy in Gases

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    The applicability of Raman spectroscopy to the investigation of gases has been greatly improved by the development of the different methods of nonlinear Raman scattering. When two laser beams, one of which has a tunable frequency, are brought to a common focus in a sample, a stimulated Raman process occurs, as soon as the frequency difference between the two lasers is equal to aRaman active rovibrational or rotational transition frequency of the sarnple, and the corresponding state is popuJated above equilibrium. The Raman resonance can be detected in different ways: by coherent anti-Stokes Raman scattering (CARS) or the corresponding Stokes process (CSRS), by again in one of the beams (stimulated Raman gain spectroscopy, SRGS) or a loss in the other one (inverse Raman spectroscopy, IRS), or even by detection of a photoacoustic signal (photoacoustic Raman spectroscopy,PARS). The selective ionisation of the excited molecules by a third ultraviolet laser pulse (ionisation detected stimulated Raman scattering, IDSRS) has considerably increased the sensitivity in special cases. The instrumental resolution of the se techniques is determined by the convoluted linewidths of the lasers used for excitation. This is of special importance for the investigation of high resolution rotation-vibrational spectra of gases

    Destructive harvesting of wild honey in Miombo woodlands affects keystone elements in the ecosystem

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    Protected areas cover 13% of the world's terrestrial surface. With increasing demands on land and with challenges of land degradation and climate change, conflicts between conservation and use are on the rise, particularly in developing countries. Effective management of these conflicts requires viable livelihood options for local land users which are in line with nature conservation goals. Consolidation of nature conservation guidelines with local land use practices may be particularly challenging where keystone species are affected or where land uses have the potential for leading to ecosystem changes. This can be an issue even in ecosystems like savannahs, where fire largely defines ecosystem structure. The Miombo woodlands, covering around 2.4 million km2 of land, harbour important diversity and are crucial for livelihoods of around 75 million people in southern Africa. As a result of various pressures, cover and biomass of Miombo woodlands are declining throughout their range. Honey harvesting is an important land use in Miombo areas, both economically and culturally. Wild bees use cavities in trees for their colonies. Harvesting practices in some places include felling of trees with honeycombs to collect the honey and setting fire for pacifying bees. This leads to starvation and death of bee colonies. Given that most tree species are bee pollinated, trees with cavities colonised by wild bees can be classified as keystone elements in these ecosystems. Although ecologically far reaching, the effects of this harvesting practice on tree population structures in Miombo woodlands have seldom been studied. We characterised the ecological effects of destructive harvesting of wild honey on tree population structure and tree species distribution in Miombo woodlands in the Niassa wildlife reserve in Mozambique. The results show that forest structure and tree diversity differed along honey harvesting intensity gradients, with the highest number of fire tolerant tree species in areas with high honey harvesting intensity, which also showed the lowest tree regeneration density and Shannon diversity. Options for reconciling livelihoods with ecosystem maintenance do exist and include non-destructive harvesting based on climbing trees with locally produced ropes and leaving larval combs behind so the colony could continue to grow

    Relearning traditional knowledge to achieve sustainability: honey gathering in the miombo woodlands of northern Mozambique

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    Mozambique’s Niassa Reserve contains Africa’s best preserved miombo woodlands. Half of the households there gather wild honey from natural hives for consumption and income. However, most collectors used destructive techniques: setting fire to the grasses under the hive tree to create smoke and then felling the tree. Cutting trees to obtain honey was the principal source of tree mortality. Trees grow very slowly, about 0.25 cm diameter [dbh]/yr, meaning an average hive tree was nearly 200 years old. Furthermore, of the trees > 20 cm dbh of species important for nectar and hives, only about 15% had cavities. Although fire is intrinsic to miombo woodlands, the increased frequency resulting from anthropogenic sources impedes regeneration of some tree species as well as affecting bees, other wildlife and villages. A few people in the reserve had learned from earlier generations how to gather honey in a nondestructive way, using certain plant species to keep bees from stinging and climbing the trees using ropes to take the honey combs out of the hives. Traditional practices included leaving the larval combs behind so the colony continued to grow. Previously, the older men who had this knowledge had not been willing to share it with younger men. The project arranged for one of the traditional honey hunters to participate in an international conference on honey collection with other indigenous collectors from around the world. This helped him recognize the value of his knowledge. The project team then arranged for him to demonstrate these traditional techniques to groups of honey hunters in nine communities within the Reserve. A yearlater, monitoring revealed that many collectors had adopted these nondestructive techniques. They found them less time consuming, and appreciated that they allowed collectors to return to the same trees repeatedly to obtain honey. Sharing traditional knowledge made honey hunting compatible with the conservation of miombo woodlands

    THREE-DIMENSIONAL DATA MODELLING FOR UNDERGROUND UTILITY NETWORK MAPPING

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    Cities around the world face an increasing need for land as density in urban areas increases rapidly. The pressure to expand a city’s space is especially acute for a city-state like Singapore. How to make better use of underground space? This issue becomes much more emergent in the urban development. In the big data era, a data-driven approach of underground spaces is necessary for the sustainable development of a city along with rapid urbanization. A reliable three dimensional (3D) digital map of utility networks is crucial for urban planners to understand one of the most impactful aspects of the underground space planning. The mapping underground utility networks is a challenging task, especially for cities with limited land resources, congested underground spaces, and a lack of uniform existing practices. This paper proposes a framework to organise the workflow from an underground utility data survey to data use. This framework includes two core parts: A 3D utility network data model that aims to convert utility survey data to 3D geospatial information, and a 3D utility cadastral data model that supports utility ownership management. It is expected that reliable and accurate information on underground utility networks can lead to a better understanding and management of underground space, which eventually contributes to better city planning, making the unseen structures visible

    A FRAMEWORK FOR RELIABLE THREE-DIMENSIONAL UNDERGROUND UTILITY MAPPING FOR URBAN PLANNING

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    To optimise the use of limited available land, land-scarce cities such as Singapore are increasingly looking towards the underground in search of more space. A good understanding of what already exists underground is essential for the planning of underground spaces. In particular, utility services make up a significant part of what exists underground. To meet planning needs, the Singapore government has initiated efforts towards bringing records of existing utility networks together in a single database and share its contents to support planning, design, and construction of underground developments. However, these records can not be relied on to support these critical processes: They are not guaranteed to represent today’s state of the underground, are not accurate or of unknown accuracy, are inconsistently modelled, and may indicate as-design information instead of as-built information. This lack of reliability leads to an increase in cost and a loss in efficiency caused by the need to repeatedly survey to locate existing utility services on-site, and can have potentially disastrous outcomes when an excavation would damage existing services. Technological advances in utility surveying and mapping devices such as Ground Penetrating Radar (GPR) and gyroscopic pipeline mapping devices offer the potential of accurately mapping utilities in three dimensions (3D) at a large scale and high speed. However, a better understanding of the benefits and limitations of these technologies in a practical context is needed, as well as their suitability for mapping to support applications such as urban planning and land administration. The Digital Underground project is a collaboration between Singapore-ETH Centre, Singapore Land Authority and the City of Zürich that aims to develop a roadmap towards a reliable 3D utility map of Singapore. To enable the development of utility mapping standards and guidelines, the 3D mapping workflow for underground utilities is studied extensively based on market research, literature study, and case studies. This work presents the beginnings of a framework for 3D mapping of underground utilities as one of the initial results of the Digital Underground project as it is in progress. From these experiences, it can be concluded that, together with existing data, data captured using various surveying methods can indeed contribute to the establishment and maintenance of a consolidated and reliable utility map. To this end, a multi-sensor, multi-data 3D mapping workflow is proposed to integrate data captured using different surveying techniques during different moments in the development lifecycle of utilities. Based on this framework, this work also identifies areas for improvement and critical gaps to be bridged that will ultimately form part of the roadmap

    Mutations in PTRH2 cause novel infantile-onset multisystem disease with intellectual disability, microcephaly, progressive ataxia, and muscle weakness

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    OBJECTIVE: To identify the cause of a so-far unreported phenotype of infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD). METHODS: We characterized a consanguineous family of Yazidian-Turkish descent with IMNEPD. The two affected children suffer from intellectual disability, postnatal microcephaly, growth retardation, progressive ataxia, distal muscle weakness, peripheral demyelinating sensorimotor neuropathy, sensorineural deafness, exocrine pancreas insufficiency, hypothyroidism, and show signs of liver fibrosis. We performed whole-exome sequencing followed by bioinformatic analysis and Sanger sequencing on affected and unaffected family members. The effect of mutations in the candidate gene was studied in wild-type and mutant mice and in patient and control fibroblasts. RESULTS: In a consanguineous family with two individuals with IMNEPD, we identified a homozygous frameshift mutation in the previously not disease-associated peptidyl-tRNA hydrolase 2 (PTRH2) gene. PTRH2 encodes a primarily mitochondrial protein involved in integrin-mediated cell survival and apoptosis signaling. We show that PTRH2 is highly expressed in the developing brain and is a key determinant in maintaining cell survival during human tissue development. Moreover, we link PTRH2 to the mTOR pathway and thus the control of cell size. The pathology suggested by the human phenotype and neuroimaging studies is supported by analysis of mutant mice and patient fibroblasts. INTERPRETATION: We report a novel disease phenotype, show that the genetic cause is a homozygous mutation in the PTRH2 gene, and demonstrate functional effects in mouse and human tissues. Mutations in PTRH2 should be considered in patients with undiagnosed multisystem neurologic, endocrine, and pancreatic disease

    A Standardized Morpho-Functional Classification of the Planet’s Humipedons

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    It was time to take stock. We modified the humipedon classification key published in 2018 to make it easier and more practical. This morpho-functional taxonomy of the topsoil (humipedon) was only available in English; we also translated it into French and Italian. A standardized morphofunctional classification of humipedons (roughly the top 30–40 cm of soil: organic and organomineral surface horizons) would allow for a better understanding of the functioning of the soil ecosystem. This paper provides the founding principles of the classification of humipedon into humus systems and forms. With the recognition of a few diagnostic horizons, all humus systems can be determined. The humus forms that make up these humus systems are revealed by measuring the thicknesses of the diagnostic horizons. In the final part of the article, several figures represent the screenshots of a mobile phone or tablet application that allows for a fast recall of the diagnostic elements of the classification in the field. The article attempts to promote a standardized classification of humipedons for a global and shared management of soil at planet level

    A standardized morpho-functional classification of the planet’s humipedons

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    It was time to take stock. We modified the humipedon classification key published in 2018 to make it easier and more practical. This morpho-functional taxonomy of the topsoil (humipedon) was only available in English; we also translated it into French and Italian. A standardized morphofunctional classification of humipedons (roughly the top 30–40 cm of soil: organic and organomineral surface horizons) would allow for a better understanding of the functioning of the soil ecosystem. This paper provides the founding principles of the classification of humipedon into humus systems and forms. With the recognition of a few diagnostic horizons, all humus systems can be determined. The humus forms that make up these humus systems are revealed by measuring the thicknesses of the diagnostic horizons. In the final part of the article, several figures represent the screenshots of a mobile phone or tablet application that allows for a fast recall of the diagnostic elements of the classification in the field. The article attempts to promote a standardized classification of humipedons for a global and shared management of soil at planet level

    A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic

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    The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world
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