We introduce an optimization framework for the reduction of support structures required by 3D printers based on Fused Deposition Modeling (FDM) technology. The printers need to connect overhangs with ...the lower parts of the object or the ground in order to print them. Since the support material needs to be printed first and discarded later, optimizing its volume can lead to material and printing time savings. We present a novel, geometry‐based approach that minimizes the support material while providing sufficient support. Using our approach, the input 3D model is first oriented into a position with minimal area that requires support. Then the points in this area that require support are detected. For these points the supporting structure is progressively built while attempting to minimize the overall length of the support structure. The resulting structure has a tree‐like shape that effectively supports the overhangs. We have tested our algorithm on the MakerBot® Replicator™ 2 printer and we compared our solution to the embedded software solution in this printer and to Autodesk® Meshmixer™ software. Our solution reduced printing time by an average of 29.4% (ranging from 13.9% to 49.5%) and the amount of material by 40.5% (ranging from 24.5% to 68.1%).
Smallholders are crucial for global sustainability given their importance to food and nutritional security, agriculture, and biodiversity conservation. Worldwide smallholders are subject to expanded ...telecoupling whereby their social-ecological systems are linked to large-scale socioeconomic and environmental drivers. The present research uses the synthesis of empirical evidence to demonstrate smallholder telecoupling through the linkages stemming from the global-level integration of markets (commodity, labor, finance), urbanization, governance, and technology. These telecoupling forces are often disadvantageous to smallholders while certain conditions can contribute to the potential sustainability of their social-ecological systems. Case studies were chosen to describe sustainability opportunities and limits involving smallholder production and consumption of high-agrobiodiversity Andean maize amid telecoupled migration (Bolivia), the role of international eco-certification in smallholder coffee-growing and agroforests (Colombia), smallholder organic dairy production in large-scale markets and technology transfer (upper Midwest, U.S.A.), and smallholders’ global niche commodity production of argan oil (Morocco). These case studies are used to identify the key challenges and opportunities faced by smallholders in telecoupling and to develop a conceptual framework. This framework specifies the integrated roles of global systems together with influential public and private institutions operating at multiple scales including the national level. The framework also integrates the local dynamics of smallholders’ multiple land use units and their socioeconomic and environmental variation. Spatial spillover effects in smallholder landscapes are an additional element. This framework further establishes the unRomantic, nonteleological, and antifetishistic view of smallholders. It provides specific insights on the multilevel dynamics of smallholder telecoupling and potential sustainability opportunities that can strengthen livelihoods, biodiversity conservation, and food and nutritional security. These insights are concluded to be valuable to environmental, agricultural, and food scientists and scholars (both biogeophysical sciences and social sciences), policy makers, institutional analysts, development specialists and practitioners, social justice activists, and others seeking to advance global sustainability including sustainable development.
Despite its theoretical prominence and sound principles, integrated pest management (IPM) continues to suffer from anemic adoption rates in developing countries. To shed light on the reasons, we ...surveyed the opinions of a large and diverse pool of IPM professionals and practitioners from 96 countries by using structured concept mapping. The first phase of this method elicited 413 open-ended responses on perceived obstacles to IPM. Analysis of responses revealed 51 unique statements on obstacles, the most frequent of which was "insufficient training and technical support to farmers." Cluster analyses, based on participant opinions, grouped these unique statements into six themes: research weaknesses, outreach weaknesses, IPM weaknesses, farmer weaknesses, pesticide industry interference, and weak adoption incentives. Subsequently, 163 participants rated the obstacles expressed in the 51 unique statements according to importance and remediation difficulty. Respondents from developing countries and high-income countries rated the obstacles differently. As a group, developing-country respondents rated "IPM requires collective action within a farming community" as their top obstacle to IPM adoption. Respondents from high-income countries prioritized instead the "shortage of well-qualified IPM experts and extensionists." Differential prioritization was also evident among developing-country regions, and when obstacle statements were grouped into themes. Results highlighted the need to improve the participation of stakeholders from developing countries in the IPM adoption debate, and also to situate the debate within specific regional contexts.
PackMerger: A 3D Print Volume Optimizer Vanek, J.; Galicia, J. A. Garcia; Benes, B. ...
Computer graphics forum,
September 2014, Letnik:
33, Številka:
6
Journal Article
Recenzirano
We propose an optimization framework for 3D printing that seeks to save printing time and the support material required to print 3D shapes. Three‐dimensional printing technology is rapidly maturing ...and may revolutionize how we manufacture objects. The total cost of printing, however, is governed by numerous factors which include not only the price of the printer but also the amount of material and time to fabricate the shape. Our PackMerger framework converts the input 3D watertight mesh into a shell by hollowing its inner parts. The shell is then divided into segments. The location of splits is controlled based on several parameters, including the size of the connection areas or volume of each segment. The pieces are then tightly packed using optimization. The optimization attempts to minimize the amount of support material and the bounding box volume of the packed segments while keeping the number of segments minimal. The final packed configuration can be printed with substantial time and material savings, while also allowing printing of objects that would not fit into the printer volume. We have tested our system on three different printers and it shows a reduction of 5–30% of the printing time while simultaneously saving 15–65% of the support material. The optimization time was approximately 1 min. Once the segments are printed, they need to be assembled.
We propose an optimization framework for 3D printing that seeks to save printing time and the support material required to print 3D shapes. 3D printing technology is rapidly maturing and may revolutionize how we manufacture objects. The total cost of printing, however, is governed by numerous factors which include not only the price of the printer but also the amount of material and time to fabricate the shape. Our PackMerger framework converts the input 3D watertight mesh into a shell by hollowing its inner parts. The shell is then divided into segments. The pieces are then tightly packed using optimization. The optimization attempts to minimize the amount of support material and the bounding box volume of the packed segments.
•2.0–2.5 billion smallholders are key to sustainable intensification and food security.•Sustainable intensification (SI) and ecological intensification (EI) require focus.•SI/EI depend on spatial ...dynamics at region and landscape scales.•Gendered livelihoods (e.g. migration) influence smallholder SI/EI and food security.•Agrobiodiversity is highly connected to spatial and livelihood dimensions of SI/EI.•A spatial- gender-agrobiodiversity framework can yield policy insights for SI/E.
Sustainable intensification (SI) and ecological intensification (EI) are promoted globally to strengthen food security and ensure environmental sustainability. Recent focus on land and agri-food systems of smallholders urges we address SI and EI through rethinking crucial social–ecological processes and spatial patterns. Principal findings underscore: firstly, the dynamics of differentiated, relational spaces of smallholder intensification/disintensification at region and landscape scales that include a polarization trend; secondly, gendered livelihood strategies across spatially differentiated landscapes influenced by smallholder migration and expanded gendering of land and agri-food systems; and finally, complex interactions of agrobiodiversity and agroecosystems mediated by smallholder and gendered knowledge systems across peri-urban to remote rural landscapes. The conclusion discusses policy implications of the spatial, gender, and agrobiodiversity dynamics of smallholder SI/EI.
Matrix Gla protein (MGP), a natural inhibitor of calcification, strongly correlates with the extent of coronary calcification. Vitamin K is the essential cofactor for the activation of MGP. The ...nonphosphorylated-uncarboxylated isoform of MGP (dp-ucMGP) reflects the status of this vitamin. We investigated whether there is an association between dp-ucMGP and stiffness of elastic and muscular-type large arteries in a random sample from the general population. In a cross-sectional design, we analyzed 1087 subjects from the Czech post-MONICA study. Aortic and femoro-popliteal pulse wave velocities (PWVs) were measured using a Sphygmocor device. Dp-ucMGP concentrations were assessed in freshly frozen samples by enzyme-linked immunosorbent assay methods using the InaKtif MGP iSYS pre-commercial kit developed by IDS and VitaK. Aortic PWV significantly (P<0.0001) increased across the dp-ucMGP quartiles. After adjustment for all potential confounders, aortic PWV independently correlated with dp-ucMGP (with beta coefficient (s.d.) 11.61 (5.38) and P-value=0.031). In a categorized manner, subjects in the top quartile of dp-ucMGP (⩾ 671 pmol l(-1)) had a higher risk of elevated aortic PWV, with corresponding adjusted odds ratio (95% confidence interval) 1.73 (1.17-2.5). In contrast, no relation between dp-ucMGP and femoro-popliteal PWV was found. In conclusion, increased dp-ucMGP, which is a circulating biomarker of vitamin K status and vascular calcification, is independently associated with aortic stiffness, but not with stiffness of distal muscular-type arteries.
Soils of the Andean highlands are under threat from cropping system intensification. Improved forage-based fallows offer great promise to address this issue, but research is needed to better ...understand the potential of species mixtures vs. monocultures to support multiple farmer objectives, especially forage production and soil conservation. We used a pot study to quantify above- and belowground biomass production as well as the total N uptake of grass–legume pairs between five grasses: (1) oat (Avena sativa), (2) ryegrass (Lolium multiflorum), (3) festulolium (Lolium × Festuca genera), (4) brome grass (Bromus catharticus), and (5) orchard grass (Dactylis glomerata), and four legumes: (1) vetch (Vicia dasycarpa), (2) red clover (Trifolium pratense), (3) black medic (Medicago lupulina), and (4) alfalfa (Medicago sativa) relative to the performance of each species in monoculture within two soils from the central Peruvian Andes. Grass–legume bicultures demonstrated significant overyielding, producing 65% and 28% more total dry biomass and total N uptake on average than monocultures. Aboveground biomass of bicultures was significantly influenced by the species of legume present, while belowground biomass was more affected by the grass species in the mixture. When evaluating the growth of each species separately, our findings indicate that overyielding was driven more by the enhanced growth of grasses relative to legumes. Our findings indicate that combining key functional groups (e.g., grass and legume, annual and perennial) offers great promise for developing improved fallows for supporting soil health and productivity in Andean agroecosystems.
Patients with schizophrenia commonly encounter a variety of sleep disorders. Disturbed sleep can be found in 30-80% of patients, depending on the degree of psychotic symptomatology. Difficulty ...falling asleep, maintaining, or achieving restful sleep is associated with symptom severity and has been reported as a prodromal symptom of psychotic relapse. Although some sleep disorders improve with antipsychotic treatment, in many cases, even during disease remission, sleep continues to be fragmented, or even different pathophysiological mechanism is causing sleep disruption. Moreover, it may be complicated if the patient needs specific treatment, such as positive airway pressure (PAP) therapy, due to sleep-disordered breathing. The article presents case reports of patients with schizophrenia with sleep disturbances. As presented in our case reports, cognitive behavioral therapy seems effective in treating comorbid insomnia, even in patients with schizophrenia. The second and third case reports emphasise the need for broader clinical considerations, a cross-diagnostic approach, and cooperation in care for patients with severe mental disorders.
BACKGROUND AND AIMS: We sought to understand biochar’s role in promoting plant phosphorus (P) access via arbuscular mycorrhizas (AM), focusing on whether P solubility and biochar-P proximity altered ...AM enhancement of P uptake in a mycorrhizal crop legume. METHODS: A greenhouse study compared feedstock-derived P with 50 mg P pot⁻¹ of sparingly soluble FePO₄ (Fe-P) or soluble NaH₂PO₄ (Na-P) at different proximities to biochar (co-pyrolyzed, mixed with biochar, mixed with soil) on Phaseolus vulgaris P uptake, specific root length (SRL), AM colonization, AM neutral lipids, and microbial biomass-P. RESULTS: Biochar increased AM colonization by 6 % (p < 0.01) and increased Fe-P uptake from 3.1 to 3.8 mg plant⁻¹, with AM-related Fe-P uptake increased by 12 % (p < 0.05). Regardless of proximity, biochar applied with Fe-P was enriched (>2×) with AM hyphae. Biochar-P proximity did not alter P uptake, but shifted uptake towards AM for Fe-P and roots for Na-P. Soluble P located on biochar increased total plant + microbial P (p < 0.05). Biochar reversed (p < 0.05) reductions in SRL induced by AM. CONCLUSIONS: Biochar enhanced AM’s access to sparingly soluble P, and root/microbial access to soluble P. Biochar augments sparingly soluble P uptake at scales larger than biochar particles, perhaps by reducing P sorption or facilitating root/hyphal exploration.
The overarching importance of sleep was further emphasized during the pandemic of COVID-19. The subjects infected by COVID-19 frequently experience sleep disturbances; some are long-lasting problems ...and decrease the quality of life. Insomnia is the most studied sleep disorder associated with COVID-19. Insomnia affects patients who have experienced an infection and the general population. Good sleep is important in maintaining mental and physical health, including immune system functions. The interconnections between insomnia, the immune system, and COVID-19 are complex. Insomnia triggers numerous immune system dysregulations and makes individuals more vulnerable to respiratory infections. This narrative review overviews the influence of the COVID-19 pandemic on the immune system through sleep disorders.
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