Low-power transistorized circuit provides staircase waveform

A low input power transistorized circuit is used to generate a staircase waveform of high step uniformity. Other characteristics are low step droop, fast transition time, and no feedback

Can’t See the Wood for the Trees: The Returns to Farm Forestry in Ireland

working paperThe period 2007-2009 witnessed considerable variability in the price of outputs such as milk and cereals and this was compounded by a high degree of volatility in the price of inputs such as fertilizer, animal feed and energy. Previously, Irish farms have used the returns to off-farm employment as well as agricultural support payments such as the Single Farm Payment (SFP) and the Rural Environmental Protection Scheme (REPS) to protect their living standards against low and uncertain agricultural market returns. However, the downturn in the Irish economy has led to a reduction in the availability of off-farm employment and also the discontinuation of REPS. This may lead to an increase in afforestation on Irish farms, as forestry offers greater certainty through the provision of an annual premium in addition to the SFP. However, the decision to afforest represents a significant long-term investment decision that should not be entered into without careful economic consideration. The aim of this paper is to use the Discounted Cash Flow (DCF) analysis method to calculate the returns to forestry under alternative opportunity costs associated with conventional agricultural activities being superseded. The returns to forestry are calculated using the Forestry Investment Value Estimator (FIVE). These returns were then incorporated in the DCF model along with the returns to five conventional agricultural enterprises, which would potentially be superseded by forestry. This approach allows for the calculation of the Net Present Value (NPV) of three forestry scenarios

Saving Seeds: The Svalbard Global Seed Vault, Native American Seed Savers, and Problems of Property

To put it simply, seeds are the essence of life. Without their varied yields, the earth would have no agriculture, no livestock, no food systems, no ecological stability. In all shapes, sizes, and distributions, seeds are genetic powerhouses that store life\u27s codes; they are as essential a resource as the water and soil at nourish them. Nonetheless, mounting evidence demonstrates steady erosion of the seed biodiversity necessary for viable food systems. Some seed varieties have been unable to adapt as habitats change or shrink, non- commercial seed-saving techniques have disappeared along with community elders, and a relatively small number of hybrid and transgenic commodity crop varieties – none of which yield useful seeds – dominate global agriculture while the botanical populations of historic landraces and their wild cousins decline. Political dangers abound as well; war and cial rest have decimated seed banks in Afghanistan, for example, and it is feared that some unique local varieties from other locations may have been permanently lost.https://scholarworks.uvm.edu/fss2014/1006/thumbnail.jp

Direct observation of the picosecond dynamics of I_2-Ar fragmentation

Picosecond real‐time observations of the dynamics of I_2–Ar fragmentation are reported. The state‐to‐state rates, k(ν^i,,ν^f,), are directly measured and related to the homogeneous broadening of the initial state, and to product state distributions in the exit channel. Comparisons with different theories of vibrational (and electronic) predissociation are made

Effects of Volcanic Emissions on Clouds During Kilauea Degassing Events

Aerosols influence Earths radiative balance directly by scattering and absorbing solar radiation, and indirectly by modifying cloud properties. Current scientific consensus indicates that these effects may offset as much as 50% of the warming due to greenhouse gas emissions. Over the last two decades dramatic volcanic events in Hawaii have produced localized aerosol emissions in otherwise clean environments. These are natural experiments" where the aerosol effects on clouds and climate can be partitioned from other effects like meteorology and industrial emissions. Therefore, these events provide a unique opportunity to learn about possible effects of aerosol pollution on climate through cloud modification. In this work we use the version 5 of the NASA Goddard Earth Observing System (GEOS-5) and satellite retrievals to analyze and evaluate the strength of the aerosol indirect effect on liquid and ice clouds during the 2008 and 2018 Kilauea degassing events using different emissions scenarios (0, 1, and 5 actual emissions). Our results suggested that the 2018 event was stronger and more regionally significant with respect to cloud formation process for both liquid and ice clouds, while the 2008 affected local liquid clouds only. GEOS-5 predictions reproduced spatial patterns for all parameters, however better precision could be gained by using more accurate plume parameters for height and ash concentration

Functionele levensduur van minerale afdichtingsmaterialen en kunststoffen in vloeistofdichte eindafwerking van stortplaatsen

De levensduur van zandbentoniet, Trisoplast, en bentonietmatten wordt hoofdzakelijk bepaald door het niveau van de totale concentratie en de verhouding tussen een- en tweewaardige ionen in de bodemoplossing (uitgedrukt in een SAR-waarde). Voor Hydrostab is het stabiel blijven van het vochtgehalte van belang. Verandering van vochtgehalte in Hydrostab is niet waarschijnlijk, zodat mag worden aangenomen dat deze duurzaam is. Goed aangelegde zand-bentoniet en Trisoplast behouden hun functie "eeuwigdurendbij geringere zoutconcentratie in de bodemoplossing dan respectievelijk 115 en 225 meq/l, ongeacht de SAR-waarde. Bentonietmatten verlangen een van de concentratie afhankelijke minimale SAR-waarde. In steunlagen treft men concentraties aan van minder dan10 tot circa 500 meq/l en SAR-waarden van minder dan 0,35 tot meer dan 5. In de meeste gevallen zullen de minerale afdichtingen hun functie "eeuwigdurend" behouden. Verlenging van levensduur door toeslag van soda aan de steunlaag is onder bepaalde kritieke omstandigheden mogelijk, maar kan niet als generieke maatregel worden toegepast. Voor kunststoffen zijn de belangrijkste degradatieprocessen thermische oxidatie, langzame scheurgroei en hydrolyse. De microbiologische afbraak van de toegepaste kunststoffen is verwaarloosbaar. Een levensduur van 100 jaar voor geomembranen, drainagelagen, drainageleidingen en weefsels in bentonietmatten is haalbaar, mits ze zijn vervaardigd uit een beperkt aantal grondstoffen grades, waarvan de samenstelling is geoptimaliseerd op duurzaamheid

Polygenic risk scores in imaging genetics: Usefulness and applications

Genetic factors account for up to 80% of the liability for schizophrenia and bipolar disorder. Genome-wide association studies (GWAS) have successfully identified several single nucleotide polymorphisms (SNPs) and genes associated with increased risk for both disorders. Single SNP analyses alone do not address the overall genomic or polygenic architecture of psychiatric disorders as the amount of phenotypic variation explained by each GWAS-supported SNP is small whereas the number of SNPs/regions underlying risk for illness is thought to be very large. The polygenic risk score models the aggregate effect of alleles associated with disease status present in each individual and allows us to utilise the power of large GWAS to be applied robustly in small samples. Here we make the case that risk prediction, intervention and personalised medicine can only benefit with the inclusion of polygenic risk scores in imaging genetics research