Science and Technology for Development in a Postcolonial World. Negotiations at the United Nations, 1960–1980

Ever since the early 1960s, the United Nations has acknowledged science and technology as integral components of developmental policies. While this connection was initially perceived as the application of findings from scientific research conducted in the Global North, by the 1970s, in the context of negotiations for a New International Economic Order, attention shifted towards the structures of the global management of science. Accordingly in 1979 the UN Conference on Science and Technology for Development discussed possibilities of strengthening scientific and technological research and teaching, particularly in developing countries. During subsequent negotiations conflicts erupted over the question of how to finance programs supporting science. When the G?77 nations presented plans involving automatic financing schemes, these concepts proved incompatible with the insistence of important industrialized countries that all financial contributions should be voluntary. These discussions appeared to be concerned with the size of financial contributions. In a larger perspective, however, they reflected fundamentally different concepts of a world order, turning science and technology into a medium for far-reaching debates about questions of global development and justice.     

Fertilizer value and nitrogen transfer efficiencies with clover-grass ley biomass based fertilizers

In temperate regions, legume-based green manures are a key element of organic rotations. However, specialized farms lack sufficient mobile organic fertilizers. To gain a better understanding of the N flows and the nitrogen (N) and phosphorus (P) fertilizer value of different clover-grass-based fertilizers (biogas digestate, compost, silage and fresh clover-grass obtained from clover-grass ley biomass), we assessed their fertilizer value. Nitrogen and P offtake by the ryegrass was used to assess the short-term effects. The data were completed using model calculations to assess the field-to-field N-transfer efficiencies and the overall N-transfer efficiencies. The greatest plant N offtake was achieved with digestates (64%) and the lowest from the compost (6%) and solid farmyard manure (14%). The mineralization rate was positively related to the NH₄ ⁺–N/total N ratio (P < 0.01, r² = 0.82). The model calculations indicate that the overall short-term N-transfer efficiencies are driven by the field-to-field N-transfer efficiency and the field-to-crop transfer efficiency. However, in the long term, model calculations indicate that a high field-to-field N-transfer efficiency is the key strategic approach when aiming to achieve cropping systems with a high overall long-term N-transfer efficiency. Consequently, the results showed that aerobic decomposition (composting) significantly lowered field-to-field as well as field-to-crop N-transfer rates. The relative P use efficiency strongly differed among the fertilizers. In particular, freshly cut clover-grass and solid manure increased P availability and led to an increase of plant P offtake that was higher than the amount of P supplied.     

Online risk-based authentication using behavioral biometrics

In digital home networks, it is expected that independent smart devices communicate and cooperate with each other, without the knowledge of the fundamental communication technology, on the basis of a distributed operating system paradigm. In such context, securing the access rights to some objects such as data, apparatus, and contents, is still a challenge. This paper introduces a risk-based authentication technique based on behavioral biometrics as solution approach to tackle this challenge. Risk-based authentication is an increasingly popular component in the security architecture deployed by many organizations to mitigate online identity fraud. Risk-based authentication uses contextual and historical information extracted from online communications to build a risk profile for the user that can be used accordingly to make authentication and authorization decisions. Existing risk-based authentication systems rely on basic web communication information such as the source IP address or the velocity of transactions performed by a specific account, or originating from a certain IP address. Such information can easily be spoofed, and as such, put in question the robustness and reliability of the proposed systems. In this paper, we propose a new online risk-based authentication system that provides more robust user identity information by combining mouse dynamics and keystroke dynamics biometrics in a multimodal framework. We propose a Bayesian network model for analyzing free keystrokes and free mouse movements involved in web sessions. Experimental evaluation of our proposed model with 24 participants yields an Equal Error Rate of 8.21 %. This is very encouraging considering that we are dealing with free text and free mouse movements, and the fact that many web sessions tend to be very short.     

Adoption of the Internet for knowledge acquisition in R&D processes

This research investigated Internet-based knowledge search patterns of engineers and scientists working in R&D for companies in the pharmacological and information technology sectors in Israel. Building on earlier work that considers the multidimensional nature of the relative advantage construct, we examine how perceptions of learning, informational convenience, and trust affected intentions to use the Internet to acquire new knowledge. In particular, these perceptions were studied with regard to both active and passive modes of interaction. We also considered here which types of technological knowledge are acquired by researchers, and how that differs across two professional communities of practice – scientists and engineers. This study sheds light on how R&D workers perceive the relative advantage of acquiring necessary knowledge through passive and active modes of communication with other researchers that are facilitated by the Internet. Findings are of interest to the literature on knowledge spillover because the capability of an organisation to acquire, disseminate, and exploit knowledge is crucial to R&D efforts.     

Multiparametric high-resolution imaging of barley embryos by multiphoton microscopy and magnetic resonance micro-imaging

Nonlinear optical microscopy and magnetic resonance imaging (MRI) address different properties of the sample and operate on different geometrical scales. MRI maps density and mobility of molecules tracking specific molecular signatures. Multiphoton imaging profits from the nonlinear absorption of light in the focus of a femtosecond laser source stimulating the autofluorescence of biomolecules. As this effect relies on a high light intensity, the accessible field of view is limited, but the resolution is very high (a few hundred nanometers). Here, we aim to link the different accessible scales and properties addressed in the different techniques to obtain a synoptic view. As model specimen we studied embryos of barley. Multiphoton stimulated autofluorescence images and images of second harmonic generation are achieved even down to low magnification (10x), low numerical aperture (N.A. 0.25) conditions. The overview images allowed morphological assignments and fluorescence lifetime imaging provides further information to identify accumulation of endogenous fluorophores. The second, complementary contribution from high-resolution MR images provides a 3D model and shows the embedding of the embryo in the grain. Images of the proton density were acquired using a standard 3D spin-echo imaging pulse sequence. Details directly comparable to the low magnification optical data are visible. Eventually, passing from the MR images of the whole grain via low magnification to high resolution autofluorescence data bridges the scale barrier, and might provide the possibility to trace transport and accumulation of, e.g., nutrients from large structure of the plant to the (sub-) cellular level.     

Functional Patterning of Biopolymer Thin Films Using Enzymes and Lithographic Methods

Two different lithographic techniques for the patterning of thin biopolymer films are developed. The first method is based on using a microstructured elastomeric mold for the structuring of thin films of regenerated cellulose. The thin films are manufactured by spin‐coating of trimethylsilyl cellulose (TMSC) and subsequent regeneration. The microchannels formed by the mold and the cellulose film are filled with a cellulase solution by capillary action. In the areas exposed to the enzyme solution, the cellulose film is digested, whereas the area in contact with the mold is protected from the enzymatic activity. Optical thickness measurements, atomic force microscopy and fluorescent staining confirm a successful patterning of cellulose on several substrates by this method. The second method is based on the structured regeneration of thin TMSC films. TMSC surfaces are protected with metal masks and exposed to vapors of hydrochloric acid. These treatments result in hydrophilic cellulose structures surrounded by hydrophobic TMSC with differing physicochemical properties. Treatments of the obtained structures with cellulases allow the selective removal of pure cellulose, whereas a TMSC pattern remains on the surface. These TMSC can be regenerated back to pure cellulose by treatments with vapors of hydrochloric acid. The developed methods allow the effective fabrication of micropatterned biopolymer thin films suitable for further functionalization and application in, e.g., bioanalytical devices. This is shown by the immobilization and detection of single‐stranded DNA on structured cellulose surfaces. Owing to the versatility of both patterning approaches the methods can be further extended to other combinations of substrates and enzymes.     

Stability of CdTe/CdS thin-film solar cells

The recent literature regarding the stability of CdTe/CdS photovoltaic cells (as distinguished from modules) is reviewed. Particular emphasis is given to the role of Cu as a major factor that can limit the stability of these devices. Cu is often added to improve the ohmic contact to p-CdTe and the overall cell photovoltaic performance. This may be due to the formation of a Cu₂Te/CdTe back contact. Excess Cu also enhances the instability of devices when under stress. The Cu, as Cu⁺, from either Cu₂Te or other sources, diffuses via grain boundaries to the CdTe/CdS active junction. Recent experimental data indicate that Cu, Cl and other diffusing species reach (and accumulate at) the CdS layer, which may not be expected on the basis of bulk diffusion. These observations may be factors in cell behavior and degradation, for which new mechanisms are suggested and areas for future study are highlighted. Other possible Cu-related degradation mechanisms, as well as some non-Cu-related issues for cell stability are discussed.     

On the Cyclic Softening Mechanisms of Reduced Activity Ferritic/Martensitic Steels

Low‐cycle fatigue tests were performed in three different ferrite/martensite steels, i.e., the European RAFM steel EUROFER 97 and the commercials AISI 410 and AISI 420, at room temperature (RT) and at 550°C. After the first few cycles, a cyclic softening that continues up to failure is observed for all these steels. The cyclic softening exhibited by AISI 420 is less pronounced than for the other two steels. The comparison between the mechanical responses of the materials was based on the study of the flow stress components, i.e., the friction and the back stresses, and their correlation with the microstructure evolution. In most cases, the strong cyclic softening observed is produced by the decreasing stress values exhibited by both stress components. However, at RT, for AISI 420, the back stress does not present variation during cycling. The decrease of the free dislocation density inside the subgrains and the growth of the mean subgrain size represent the main microstructural evolution.