31 research outputs found
Stem-Level Bucking Pattern Optimization in Chainsaw Bucking Based on Terrestrial Laser Scanning Data
Cross-cutting of a tree into a set of assortments (»bucking pattern«) presents a large potential
for optimizing the volume and value recovery; therefore, bucking pattern optimization has been
studied extensively in the past. However, it has not seen widespread adoption in chainsaw bucking,
where time consuming and costly manual measurement of input parameters is required for
taper curve estimation. The present study investigated an alternative approach, where taper
curves are fit based on terrestrial laser scanning data (TLS), and how deviations from observed
taper curves (REF) affect the result of bucking pattern optimization. In addition, performance
of TLS was compared to a traditional, segmental taper curve estimation approach (APP) and
an experienced chainsaw operator’s solution (CHA).
A mature Norway Spruce stand was surveyed by stationary terrestrial laser scanning. In TLS,
taper curves were fit by a mixed-effects B-spline regression approach to stem diameters extracted
from 3D point cloud data. A network analysis technique algorithm was used for bucking
pattern optimization during harvesting. Stem diameter profiles and the chainsaw operator’s
bucking pattern were obtained by manual measurement. The former was used for post-operation
fit of REF taper curves by the same approach as in TLS. APP taper curves were fit based on
part of the data. For 35 trees, TLS and APP taper curves were compared to REF on tree, trunk
and crown section level. REF and APP bucking patterns were optimized with the same algorithm
as in TLS. For 30 trees, TLS, APP and CHA bucking patterns were compared to REF on
operation and tree level.
Taper curves were estimated with high accuracy and precision (underestimated by 0.2 cm on
average (SD=1.5 cm); RMSE=1.5 cm) in TLS and the fit outperformed APP. Volume and value
recovery were marginally higher in TLS (0.6%; 0.9%) than in REF on operation level, while
substantial differences were observed for APP (–6.1%; –4.1%). Except for cumulated nominal
length, no significant differences were observed between TLS and REF on tree level, while APP
result was inferior throughout. Volume and value recovery in CHA was significantly higher
(2.1%; 2.4%), but mainly due to a small disadvantage of the optimization algorithm.
The investigated approach based on terrestrial laser scanning data proved to provide highly
accurate and precise estimations of the taper curves. Therefore, it can be considered a further
step towards increased accuracy, precision and efficiency of bucking pattern optimization in
chainsaw bucking
Teaching in Focus: The value of implementing a program-specific teaching support project for staff wellbeing and student success
This work is licensed under a Creative Commons Attribution 4.0 Licence. As an open access journal, articles are free to use, with proper attribution, in educational and other non-commercial settings.This paper reports on a program-level teaching support initiative that was implemented in a Health Sciences undergraduate degree with a large and highly casualised teaching team. It has been argued that to improve student retention and success, universities need to consider implementing comprehensive teaching support models that address institutional, program, and individual level needs. We report on the implementation of our project and reflect on participant feedback, which demonstrated the value of the program for improving staff wellbeing. We argue that introducing support strategies for staff at a local level is essential not only for delivery of high quality learning experiences, but also for staff wellbeing which, in turn, has important implications for student success and retention
Measurement of Individual Tree Parameters with Carriage-Based Laser Scanning in Cable Yarding Operations
Introduction: Cable yarding is a technology that enables efficient and sustainable use of timber resources in mountainous areas. Carriages as an integral component of cable yarding systems have undergone significant development in recent decades. In addition to mechanical and functional developments, carriages are increasingly used as carrier platforms for various sensors. The goal of this study was to assess the accuracy of individual standing tree and stand variable estimates obtained by a mobile laser scanning system mounted on a cable yarder carriage.
Methods: Eight cable corridors were scanned across two forest stands. Four different scan variants were conducted, differing in the movement speed of the carriage and the direction of movement during scanning. An algorithm for tree detection, diameter and height estimation was applied to the 3D datasets and evaluated against manual tree measurements.
Results: The analysis of the 3D scans showed that the individual tree parameters strongly depend on the scan variant and the distance of each individual tree to the skyline. This was due to changing 3D point densities and occlusion effects. It turned out that scan variant 1, in which the scan was performed during slow carriage movement downwards and back upwards again, was advantageous. At a distance of 10 m, which is half of the recommended corridor spacing of 20 m for whole tree cable yarding, 95.44% of the trees in stand 1 and 92.16% of the trees in stand 2 could be detected automatically. The corresponding root mean sqare errors of the diameter at breast height estimatimations were 1.59 cm and 2.23 cm, respectively. The root mean square errors of the height measurements were 2.94 m and 4.63 m.
Conclusions: The results of this study can help to further advance the digitization of cable yarding and timber flow from the standing tree to the sawmill. However, this requires further development steps in cable yarder, carriage, and laserscanner technology. Furthermore, there is also a need for more efficient software routines to take the next steps towards precision forestry
Life-long impairment of glucose homeostasis upon prenatal exposure to psychostimulants
Maternal drug abuse during pregnancy is a rapidly escalating societal problem. Psychostimulants, including amphetamine, cocaine, and methamphetamine, are amongst the illicit drugs most commonly consumed by pregnant women. Neuropharmacology concepts posit that psychostimulants affect monoamine signaling in the nervous system by their affinities to neurotransmitter reuptake and vesicular transporters to heighten neurotransmitter availability extracellularly. Exacerbated dopamine signaling is particularly considered as a key determinant of psychostimulant action. Much less is known about possible adverse effects of these drugs on peripheral organs, and if in utero exposure induces lifelong pathologies. Here, we addressed this question by combining human RNA-seq data with cellular and mouse models of neuroendocrine development. We show that episodic maternal exposure to psychostimulants during pregnancy coincident with the intrauterine specification of pancreatic beta cells permanently impairs their ability of insulin production, leading to glucose intolerance in adult female but not male offspring. We link psychostimulant action specifically to serotonin signaling and implicate the sex-specific epigenetic reprogramming of serotonin-related gene regulatory networks upstream from the transcription factor Pet1/Fev as determinants of reduced insulin production.Peer reviewe
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Legal and ethical framework for global health information and biospecimen exchange - an international perspective.
BACKGROUND: The progress of electronic health technologies and biobanks holds enormous promise for efficient research. Evidence shows that studies based on sharing and secondary use of data/samples have the potential to significantly advance medical knowledge. However, sharing of such resources for international collaboration is hampered by the lack of clarity about ethical and legal requirements for transfer of data and samples across international borders. MAIN TEXT: Here, the International Clinical Trial Center Network (ICN) reports the legal and ethical requirements governing data and sample exchange (DSE) across four continents. The most recurring requirement is ethical approval, whereas only in specific conditions approval of national health authorities is required. Informed consent is not required in all sharing situations. However, waiver of informed consent is only allowed in certain countries/regions and under certain circumstances. The current legal and ethical landscape appears to be very complex and under constant evolution. Regulations differ between countries/regions and are often incomplete, leading to uncertainty. CONCLUSION: With this work, ICN illuminates the unmet need for a single international collaborative framework to facilitate DSE. Harmonising requirements for global DSE will reduce inefficiency and waste in research. There are many challenges to realising this ambitious vision, including inconsistent terminology and definitions, and heterogeneous and dynamic legal constraints. Here, we identify areas of agreement and significant difference as a necessary first step towards facilitating international collaboration. We propose the establishment of a working group to continue the comparison across jurisdictions, create a standardised glossary and define a set of basic principles and fundamental requirements for DSE
Technologies of contraception and abortion
Soon to turn 60, the oral contraceptive pill still dominates histories of technology in the ‘sexual revolution’ and after. ‘The pill’ was revolutionary for many, though by no means all, women in the west, but there have always been alternatives, and looking globally yields a different picture. The condom, intrauterine device (IUD), surgical sterilization (male and female) and abortion were all transformed in the twentieth century, some more than once. Today, female sterilization (tubal ligation) and IUDs are the world's most commonly used technologies of contraception. The pill is in third place, followed closely by the condom. Long-acting hormonal injections are most frequently used in parts of Africa, male sterilization by vasectomy is unusually prevalent in Britain, and about one in five pregnancies worldwide ends in induced abortion. Though contraceptive use has generally increased in recent decades, the disparity between rich and poor countries is striking: the former tend to use condoms and pills, the latter sterilization and IUDs. Contraception, a term dating from the late nineteenth century and since then often conflated with abortion, has existed in many forms, and techniques have changed and proliferated over time. Diverse local cultures have embraced new technologies while maintaining older practices. Focusing on Britain and the United States, with excursions to India, China and France, this chapter shows how the patterns observed today were established and stabilized, often despite persistent criticism and reform efforts. By examining past innovation, and the distribution and use of a variety of tools and techniques, it reconsiders some widely held assumptions about what counts as revolutionary and for whom. Analytically, it takes up and reflects on one of the main issues raised by feminists and social historians: the agency of users as patients and consumers faced with choice and coercion. By examining practices of contraception alongside those of abortion, it revisits the knotty question of technology in the sexual revolution and the related themes of medical, legal, religious and political forms of control
Endure in thin air
Ascending to high altitudes can cause severe threats for the human body. Hypoxia, the lack of oxygen due to a low atmospheric pressure is a major danger in great heights.Millions of people live or travel in elevated areas, means that mountain sickness due to hypoxia is a public health problem. The worst forms of mountain illness, known as high-altitude pulmonary edema and high-altitude cerebral edema, are potentially fatal. Due to a lack infrastructure and especially bad accessibility it is very challenging to support people with first aid or transport. The aim of this master thesis in Advanced Product Design was to explore the field of hypoxia in extreme altitudes in order to create a product solution that can contribute to overcome this threat and protect people from i
Endure in thin air
Ascending to high altitudes can cause severe threats for the human body. Hypoxia, the lack of oxygen due to a low atmospheric pressure is a major danger in great heights.Millions of people live or travel in elevated areas, means that mountain sickness due to hypoxia is a public health problem. The worst forms of mountain illness, known as high-altitude pulmonary edema and high-altitude cerebral edema, are potentially fatal. Due to a lack infrastructure and especially bad accessibility it is very challenging to support people with first aid or transport. The aim of this master thesis in Advanced Product Design was to explore the field of hypoxia in extreme altitudes in order to create a product solution that can contribute to overcome this threat and protect people from i
Endure in thin air
Ascending to high altitudes can cause severe threats for the human body. Hypoxia, the lack of oxygen due to a low atmospheric pressure is a major danger in great heights.Millions of people live or travel in elevated areas, means that mountain sickness due to hypoxia is a public health problem. The worst forms of mountain illness, known as high-altitude pulmonary edema and high-altitude cerebral edema, are potentially fatal. Due to a lack infrastructure and especially bad accessibility it is very challenging to support people with first aid or transport. The aim of this master thesis in Advanced Product Design was to explore the field of hypoxia in extreme altitudes in order to create a product solution that can contribute to overcome this threat and protect people from i
The effect of prenatal methamphetamine exposure on glucose homeostasis in offspring
Die korrekte Sekretion von Insulin als Reaktion auf eine erhöhte Glukose Konzentration im Blut ist wichtig um das Glukose Gleichgewicht aufrecht zu erhalten. Insulin wird in den β-Zellen der Langerhans’schen Inseln produziert und sezerniert. Die Dopamin Rezeptoren DRD1 und DRD2, der Dopamintransporter (DAT), der Vesikuläre Monoaminetransporter (VMAT2), L-3,4-dihydroxyphenylalanin (L-Dopa) und Dopamin wurden in den β-Zellen von Nagetieren nachgewiesen. Es wurde beobachtet, dass der Dopamin Signalweg durch Methamphetamin beeinflußt wird. Wir nehmen an, dass die Verabreichung von Methamphetamin zu einem bestimmten Zeitpunkt in der embryonalen Entwicklung Einfluß auf die Entwicklung des endokrinen Pankreas und der Langerhans’schen Insel hat und damit die adequate Insulinsekretion beeinflußt. Wir zeigen, dass die Anzahl der β-Zellen von Tieren welchen prenatal Methamphetamin verabreicht wurde, signifikant sinkt. Die Nachkommen der Methamphetamin behandelten Muttertiere zeigen ein erhöhtes Glukose Level im Blut zu Beginn und während des gesamten GTT. Weiters können wir zeigen, dass in der mit Methamphetamine behandelten INS-1E Zellen die Genexpression von DRD1 signifikant sinkt. In den 6 Wochen alten Nachkommen Methamphetamin behandelter Tiere nimmt die Anzahl der Insulin-positiven β-Zellen ab und wir untersuchten, ob dies durch Apoptosis hervorgerufen wird. Die Cleaved Caspase3 (Casp3) Immunofärbung zeigte, dass die Anzahl apoptotischer INS-1E Zellen durch eine Methamphetamin Exposition signifikant erhöht ist. Diese Resultate zeigen, dass Methamphetamin die Architektur der Langerhans’schen Inseln und die Genexpression von DRD1 beeinflußt und eine nicht angemessene Reaktion auf eine erhöhte Glukosekonzentrationen im Blut zur Folge hat.For glucose homeostasis the adequate secretion of insulin in a response to elevated glucose concentration in blood is necessary. Insulin is produced by and secreted from β-cells in the islets of Langerhans. It has been previously suggested that dopamine receptor 1 (DRD1) and dopamine receptor 2 (DRD2), dopamine transporter (DAT), vesicular monoamine transporter 2 (VMAT2), as well as dopamine itself are present in the β-cells of rodents. It was observed that dopamine signaling is affected by methamphetamine. We hypothesized that the treatment with methamphetamine at a specific time-point in embryonic development can affect the dopaminergic signaling pathway in endocrine pancreas and thus interfere with islet development and an adequate insulin secretion. We showed that the number of β-cells in 6 week old animals prenatally exposed to methamphetamine is significantly decreased. Moreover glucose tolerance test (GTT) showed that the level of glucose in the blood is elevated at baseline and throughout GTT in offspring prenatally exposed to methamphetamine. We further demonstrate that in methamphetamine treated INS-1E cells gene expression of DRD1 is significantly decreased. Because the number of insulin positive β-cells is decreased in 6 week old animals prenatally exposed to methamphetamine we examined if it is due to apoptosis. Cleaved Caspase3 (Casp3) immunostaining showed that the number of apoptotic INS-1E-cells is significantly increased upon methamphetamine exposure. These findings reveal that methamphetamine affects the architecture of islets and gene expression of DRD1 resulting in a non-adequate response to elevated blood glucose concentrations