On time-frequency analysis and time-limitedness

We study two classical problems, namely the concentration of energy problem and the truncation problem. The first problem deals with time-limited signals that have maximal energy in a certain frequency band. The second problem is about estimating the spectrum of a signal, if this signal is only known at a certain interval. Solutions of the first problem can be used to obtain good solutions for the second one by means of a preprocessing algorithm, called tapering. The truncation problem and the tapering algorithm are also studied for time-scale and time-frequency analysis, using the continuous wavelet transform and the Wigner-Ville representation

Integral representations of affine transformations in phase space with an application to energy localization problems

Applying the fractional Fourier transform and the Wigner distribution on a signal in a cascade fashion is equivalent with a rotation of the time and frequency parameters of the Wigner distribution. This report presents a formula for all unitary operators that are related to energy preserving transformations on the parameters of the Wigner distribution by means of such a cascade of operators. Furthermore, such operators are used to solve certain type of energy localization problems via the Weyl correspondence

Insects as food and feed: nutrient composition and environmental impact

Abstract Because of an increasing world population, with more demanding consumers, the demand for animal based protein is on the increase. To meet this increased demand, alternative sources of animal based protein are required. When compared to conventional production animals, insects are suggested to be an interesting protein source because they have a high reproductive capacity, high nutritional quality, and high feed conversion efficiency, they can use waste as feed and are suggested to be produced more sustainably. This thesis starts with a historical perspective on insects as food and feed, and explains why insects are expected to be more suitable production animals. In Chapter 2 the nutritional quality of insects is discussed based on a variety of insects that are commonly used as feed or food. Additionally, various environmental and dietary factors which are known to significantly affect insect chemical composition are reviewed. In Chapter 3 the direct production of greenhouse gases (GHG) and ammonia, as well as carbon dioxide emission and average daily weight gain of five insect species is quantified. Differences regarding the production of GHGs (expressed as CO2 equivalents) between insect species were mainly due to the production of methane. All species tested emitted lower amounts of GHG than cattle, had a higher growth rate than cattle or pigs, and emitted lower amounts of ammonia and either comparable or lower amounts of GHG than pigs. Results from Chapter 3 were used in a Life Cycle Assessment conducted in Chapter 4. For a mealworm production system total GHG production, energy use, and land use were quantified and compared to conventional sources of animal protein. This chapter shows that mealworms should be considered a more sustainable source of edible protein, and that a large part of their environmental impact is due to the feed they consume. In Chapter 5 four diets composed from industrial organic by-products were formulated such that they varied in protein and fat content. These diets were offered to four insect species and their feed conversion efficiency was determined. Diets used in large scale production systems were included and served as controls. Diet composition affected feed conversion efficiency in all species. It is concluded that the four investigated species are efficient production animals and can therefore be considered interesting for the production of feed or food. Furthermore, diet composition affected insect composition, indicating possibilities to tailor the composition of these insects to best meet consumers’ needs. In Chapter 6 the suitability of chicken, pig, and cow manure was compared as feed for larvae of the Black Soldier Fly, which in turn could be used as feed for conventional production animals. Newly hatched larvae were directly inoculated on moistened manure. Whereas survival was high on all three tested substrates, the development time was greatly prolonged compared to the control diet. On pig manure, more nitrogen was utilised than on chicken and cow manure, while P utilisation was highest on cow manure. A large proportion of manure nitrogen was lost in all treatments, indicating that the production system would require a way to prevent this in order to make it ecologically sound. Furthermore, to improve economic viability, shorter development times would be required. In Chapter 7 the suggestions why insects would make suitable production animals are evaluated based on both literature data, and data gathered in this thesis. Furthermore, prospects for insects as food or feed are put forward, with emphasis on the knowledge and legislation requirements for the further development of the insect production sector.</p

North American entomophagy

Eating insects is not a common Northern American practice today. However, in the past a variety of insect species was consumed in Northern America (north of Mexico including Greenland). The aim of this literature review is to provide an historical overview of North American entomophagy based upon both peer and non-peer reviewed sources on this topic. Regional differences in insect consumption and reasons for being underreported are discussed. We show that North American natives, and in certain cases colonists, collected and consumed a large variety of edible insects. These are categorized per order and where available, information on how these species were collected and processed is provided. Lastly, we mention reasons for the renewed interest in edible insects in North America, and make suggestions for future studies

Environmental Impact of the Production of Mealworms as a Protein Source for Humans - A Life Cycle Assessment

The demand for animal protein is expected to rise by 70–80% between 2012 and 2050, while the current animal production sector already causes major environmental degradation. Edible insects are suggested as a more sustainable source of animal protein. However, few experimental data regarding environmental impact of insect production are available. Therefore, a lifecycle assessment for mealworm production was conducted, in which greenhouse gas production, energy use and land use were quantified and compared to conventional sources of animal protein. Production of one kg of edible protein from milk, chicken, pork or beef result in higher greenhouse gas emissions, require similar amounts of energy and require much more land. This study demonstrates that mealworms should be considered a more sustainable source of edible protein

Meeting the global protein supply requirements of a growing and ageing population

\ua9 The Author(s) 2024.Human dietary patterns are a major cause of environmental transformation, with agriculture occupying ~ 50% of global land space, while food production itself is responsible for ~ 30% of all greenhouse gas emissions and 70% of freshwater use. Furthermore, the global population is also growing, such that by 2050, it is estimated to exceed ~ 9 billion. While most of this expansion in population is expected to occur in developing countries, in high-income countries there are also predicted changes in demographics, with major increases in the number of older people. There is a growing consensus that older people have a greater requirement for protein. With a larger and older population, global needs for protein are set to increase. This paper summarises the conclusions from a Rank Prize funded colloquium evaluating novel strategies to meet this increasing global protein need