Nitrogen fertilizer value of digestates from anaerobic digestion of animal manures and crops

After anaerobic digestion (AD) of manures for biogas production the concentration of ammonium-N is increased and the concentration of decomposable carbon in manure is decreased. That implies that the first year fertilizer value of the manure can be increased by the treatment. However, pH is also increased by AD thereby increasing the risk of ammonia losses while the lowered dry matter content on the other hand improves the manure infiltration in soil and reduces the risk of ammonia loss. Therefore the effects of AD on plant N availability can be expected to interact with the manure application method used. In stockless organic farming it has been suggested that nitrogen utilization can be improved by using anaerobic digestion of plant-based green manures, but the information about such manures is scarce. We have compared nitrogen fertilizer values of 1) pig and cattle slurries before and after AD and 2) digested plant-based manures. Mineral fertilizer replacement values (MFRV) were determined after direct injection to barley and oats crops and after surface-banding in a winter wheat crop. The manures were digested in continuously fed pilot digesters at thermophilic conditions (ca. 50°C). The manures were applied to small framed plots and grain yields and N uptake were compared to plots receiving increasing amounts of mineral N fertilizer. The three tested plant-based manures derived from crops of either grass clover, yellow lupine or a triticale-winter vetch mixture. The MFRV of total N in two different injected cattle slurries increased from 58-75% to 69-82% after AD. The MFRV of cattle slurry after surface-banding in winter wheat was much lower: 30-37% for untreated slurry and 38-49% after AD. The low availability after surface-banding can be ascribed to high ammonia volatilization. The MFRV of injected pig slurry was high and similar with and without AD: 89-91%. After surface banding of pig slurry MFRV was 75% for untreated and 87% for digested pig slurry. The plant-based manures contained a high proportion of ammonium-N (59-68% of total N) after AD and the MFRVs of total manure N were comparable to the digested cattle slurries: 73-77% after injection, but only 43-57% after surface-banding of the manure. The influence of AD of manure on N turnover in soil has also been evaluated in a soil incubation study with some of the same manures, and the differences between untreated and digested manures were more distinct in this incubation study than the observed differences in fertilizer value. We conclude that the potential plant availability of pig and cattle slurry can be increased by 10-15% points after AD. However, after surface-banding of digested manures rich in fibers, such as cattle and plant-based manures, significant ammonia loss can be expected resulting in relative poor N utilization

Labour Tax Reform, The Good Jobs and the Bad Jobs.

We analyse recent proposals to shift the tax burden away from low-paid labour, assuming a dual labour market where the 'good' high-paying jobs are rationed. A shift in the tax burden from low-paid to high-paid workers has an ambiguous effect on the level of aggregate employment while the allocation of aggregate employment is likely to be further distorted. Even if the tax reform raises total employment, economic efficiency may be reduced because labour is reallocated from high-productive to low-productive jobs. Opportunities for on--the--job search have important implications for the policy effects. When these opportunities are small, the tax reform is more likely to raise employment and welfare.

Maximal partial Latin cubes

We prove that each maximal partial Latin cube must have more than 29.289% of its cells filled and show by construction that this is a nearly tight bound. We also prove upper and lower bounds on the number of cells containing a fixed symbol in maximal partial Latin cubes and hypercubes, and we use these bounds to determine for small orders n the numbers k for which there exists a maximal partial Latin cube of order n with exactly k entries. Finally, we prove that maximal partial Latin cubes of order n exist of each size from approximately half-full (n3/2 for even n ≥ 10 and (n3 + n)/2 for odd n ≥21) to completely full, except for when either precisely 1 or 2 cells are empty

Exceptions and counterexamples: Understanding Abel's comment on Cauchy's Theorem

AbstractIt may seem odd that Abel, a protagonist of Cauchy's new rigor, spoke of “exceptions” when he criticized Cauchy's theorem on the continuity of sums of continuous functions. However, when interpreted contextually, exceptions appear as both valid and viable entities in the early 19th century. First, Abel's use of the term “exception” and the role of the exception in his binomial paper is documented and analyzed. Second, it is suggested how Abel may have acquainted himself with the exception and his use of it in a process denoted critical revision is discussed. Finally, an interpretation of Abel's exception is given that identifies it as a representative example of a more general transition in the understanding of mathematical objects that took place during the period. With this interpretation, exceptions find their place in a fundamental transition during the early 19th century from a formal approach to analysis toward a more conceptual one

Buddho–Daoism in medieval and early pre-modern China: A report on recent findings concerning influences and shared religious practices

This comprises a report on a project conducted at the Ruhr University, Bochum, on the interrelationship and exchanges between China's two major religious traditions, Buddhism and Daoism, during the medieval and early pre-modern periods. While the departure for the research was primarily concerned with the mutual exchanges of ritual techniques and technology, i.e.~ritual practices in general, concepts of ritual, ritual implements, ritual language, rituals in specific cultic contexts etc., I gradually expanded my interest to include a wider range of topics relating to the exchanges between Buddhism and Daoism in China including the appropriation of divinities and saints, integrated beliefs and practices involving elements from both religions, apocryphal writings, conceptualizations concerning specific religious themes in which ideas and beliefs from both Buddhism and Daoism were brought together. Among other issues dealt with is the manner in which such concepts of “secrecy” and “the netherworld” were formulated and constructed in the Buddho–Daoist exchanges

Subsidising consumer services: effects on employment, welfare and the informal economy

It is widely agreed that the opportunities for expansion of aggregate employment in the OECD area must be sought mainly in the private service sector. Thus,because of budgetary problems and voter resistance to higher tax rates, the scope for further expansion of public sector employment seems limited in most OECD countries. Furthermore, the primary sector will undoubtedly continue to release labour resources and, with normal growth rates, there is little prospect of a secular rise in manufacturing employment, since the increase in demand for manufactures is likely to be met through increases in labour productivity. In particular, the ongoing shifts in the international division of labour and the associated transition to the ‘knowledge-based economy’ within the OECD are likely to destroy a large number of manufacturing jobs for unskilled and lowskilled workers in the OECD area.