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Potential of hordein as a biodegradable food packaging material
Get PDFConventional plastic packaging is almost non-degradable, leading to significant
environmental concerns. As a result, developing biodegradable packaging materials has
attracted considerable attention from both industry and researchers. This study explores
the potential of hordein, a protein extracted from spent barley, as a biodegradable
packaging material. The high glutamine content and presence of hydrophobic amino acids,
such as proline, leucine, and valine, endow hordein with strong aggregation properties
and notable hydrophobicity.
However, hordein-based films tend to have poor mechanical properties. Therefore,
addition of individual plasticizers, glycerol (GLY) and PEG400 and their combinations were
investigated in this research in order to enhance its property. The composite plasticizer
formed by 25% PEG and 75% GLY demonstrated a synergistic effect, and significantly
improved tensile strength and elongation at break of hordein film. Furthermore, the optical
property of hordein film was also optimized in this research. Heat treatment was able to
unfold the protein structure, exposing thiol groups to promote cross-linking through
disulfide bonds and strengthening the protein network. Similarly, transglutaminase (TGase)
could induce covalent cross-linking by forming isopeptide bonds between glutamine and
lysine residues. To further enhance the mechanical properties of the hordein films, heat
treatment at 85oC for 30 mins and TGase added at 0, 10, 20, 30 and 40 U/g were applied
to assess their impacts on hordein film quality. Heat treatment produced a thinner film
without compromising its mechanical property, while 20 U/g TGase achieved optimal
mechanical properties. Although improvements were observed, the mechanical properties
still fell short of currently used competing alternatives.
Given hordein's excellent hydrophobicity and UV-blocking properties, the possibility of
using hordein as a supplementary ingredient to enhance the properties of starch-based
films was explored in this work. Starch films tend to be inherently brittle and sensitive to
moisture, despite their superior film-forming ability. Corn starch was identified as the
optimal base material for film production, outperforming potato and wheat starch in
comparative analyses. Hordein was incorporated into the corn starch matrix at varying
Abstract
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mass ratios (10%, 20%, 30% and 40%) to assess its effect on the properties of starch film.
The results showed that the addition of hordein significantly increased film thickness,
tensile strength (TS), and UV-blocking performance of starch film.
Overall, this study provides valuable insights into the characteristics of hordein and its
potential application in the development of biodegradable food packaging films, offering a
promising alternative to conventional plastic materials
The Big Mac index: an exact multilateral clarification
Get PDFThe Economist’s Big Mac index measures the external purchasing power of a currency relative to a common numéraire currency. The Big Mac index is based on the economic theory of absolute purchasing power parity. There are two versions of the index, namely, the Raw Big Mac index and the GDP-adjusted Big Mac index. The bilateral valuations for both versions are conditional on the common numéraire currency. For example, the common numéraire currency is always at fair value, whereas the valuations of the other currencies are measured relative to the common numéraire currency. This paper extends previous research by providing a theoretical framework to calculate exact multilateral valuations for a system of currencies. The methodological extension sheds light on a number of linkages between the bilateral valuations and the multilateral valuations for both versions of the Big Mac index
Emergence of self–organization of atmospheric moist convection, as seen through the energy–cycle in wavelet space
Get PDFThe energy cycle of a convectively–organized system, as realized by a convective–scale idealized simulation, is analyzed in wavelet space. In the equilibrium state, most of the available potential energy that is generated by convective heating is immediately converted into kinetic energy by means of buoyancy forcing, consistent with the free–ride principle. In turn, most of the generated convective kinetic energy is manifest as gravity waves propagating away from convective centers. The kinetic energy of these small–scale gravity waves is transferred upscale by their own advective nonlinearities. Finally, a large–scale circulation generated by this “inverse cascade” drives the formation of an organized structure in the precipitation field
Community-led solar energy technology adoption in rural Zambia: the role of observational learning and neighbor influence
Get PDFSolar PV technology holds significant potential for addressing energy access issues in rural Zambia. However, adoption rates remain low despite numerous interventions. This study explores the impact of community-based interventions, leveraging local networks, individual benefits, and peer consultation, on accelerating PV adoption and willingness to pay. The primary aim is to understand how social and individual benefits influence PV adoption intention and examine the relationship between visual exposure to solar technology and adoption intention. The research seeks to inform policies and interventions that promote sustainable energy access and socio-economic development in rural Zambia and similar contexts. Over 6 months, a qualitative study was conducted involving 58 interviews, 7 focus group discussions, pictorial evidence, and observational techniques. The study engaged 120 rural subsistence farmers and 16 commercial farmers across three regions of Zambia, using five local languages. The research employed the Rural Development Stakeholder Hybrid Adoption Model (RUDSHAM) that was developed for this research, which combines the Theory of Planned Behavior (TPB), the Technology Acceptance Model (TAM), and Diffusion of Innovations (DOI) theory. Findings reveal that shifting individual and community mindsets is crucial for project sustainability. Emphasizing individual benefits leads to broader community advantages as participation increases. Additionally, PV adoption and willingness to pay can be catalysed through systematic knowledge dissemination and leveraging peer and social influence. The study highlights the need for donors to deepen their understanding of poverty to make effective interventions. These insights provide a foundation for developing targeted strategies to enhance PV adoption in rural settings
Getting it wrong: biological mistake making as a cross-system, cross-scale phenomenon
Get PDFThe making of mistakes by organisms and living systems generally is an underexplored way of conceptualising biology and organising experimental research. We set out an informal account of biological mistakes and why they should be taken seriously in biological investigation. We then give an indirect defence of their importance by applying the concept of mistake making to three kinds of activity: timing, calculation, and communication. We give a range of examples to show that mistakes in these kinds of behaviour can be found across a diversity of scales and systems. We also suggest ideas for empirical research that naturally arise from these cases. The reality and potential for mistake making across such a wide range of biological entities shows that it is not a purely human phenomenon. Getting it wrong seems to be central to biology as a whole, and to be a potentially productive organising principle for generating novel research questions and experimental hypotheses
Mismanagement amid resource abundance: sovereign risk, private sector credit rationing, and economic stagnation in Colombia, 1861‒98
Get PDFThis article examines the relationship between national politics, sovereign default, credit rationing, and their effects on fiscal revenues and exports in nineteenth‐century Colombia. Using quantitative and qualitative analysis, it challenges existing narratives on Colombia's lack of sustained nineteenth‐century export‐led development, showing that sovereign default was a political choice with long‐term negative impacts. The study highlights how credit rationing and technological backwardness hindered economic growth. It argues that these policies caused Colombia's economic stagnation, leading to boom‐and‐bust cycles in export crop production. It identifies substantial growth during the liberal era and minimal growth during the regeneración period
Global surface temperatures
No full textThe Sixth Assessment Report of the Intergovernmental Panel on Climate Change stated that ”it is unequivocal that human influence has warmed the atmosphere, ocean and land”. One key piece of evidence for this is the global average of the instrumental record of surface temperature. A change in surface temperature of 1.5˚C relative to a reference “pre-industrial” period is the measure internationally agreed to mark the transition to a climate where dangerous impacts become common. This chapter will discuss the observational evidence that ensures a reliable record of the changing temperature, some of the challenges that have been overcome, and some that remain in improving that record and more fully understanding its uncertainty
Developmental trajectories of grammatical comprehension in individuals with Williams syndrome
Get PDFDespite earlier claims that language abilities are intact in individuals with Williams syndrome (WS), many studies have shown that language development is often delayed and atypical, i.e. it develops in line with different cognitive abilities compared to typically developing populations. It is unclear, however, whether general cognitive development predicts language comprehension in WS. The current study is the first to examine the development of grammatical comprehension in a large group (N=58) of individuals with WS aged 5 to 21 years old. Grammatical comprehension is key to a person’s ability to understand what is being said and engage in successful social interaction. Using cross-sectional developmental trajectories, performance on the Test Reception of Grammar (TROG-2) was shown to increase with chronological age and performance was predicted by vocabulary scores, but not non-verbal ability. In addition, there was no meaningful difference between items that contained spatial language and similar grammatical constructions that did not contain spatial language, and performance on both types of expressions was similarly predicted by vocabulary scores. Overall, these results show that grammatical development in WS is delayed but not atypical in its relationship to vocabulary
Balancing acts: bank market deregulation and the dynamics of earnings management
No full textThis study examines the impact of bank market deregulation in U.S. since 1994 on corporate earnings management decision makings. We show that bank market deregulation has led to a trade off between accrual based earnings management and real earnings management. The trade off is driven by the improved monitoring of banks since deregulation where banks pay more diligence to monitor accruals which are reverse in a short term and more relevant to the default risk banks expose to. To respond, firms engage in more real earnings management which has a long term impact on corporate performance but is less relevant to current default risk
Scottish archaeological islands: a historiographical analysis and the legacy of antiquarian research
Get PDFCrannogs, enigmatic artificial islands dotting the landscapes of Scotland and Ireland, have been subjects of intrigue and debate for centuries. These complex sites exhibit a remarkable time-depth of use, often revealing multiple phases or periods, coupled with a great diversity in their structural forms and settings. Moreover, the extensive yet fragmented early historiography of crannog research has left a lasting legacy on our modern understandings and interpretations of these sites. Adding to the complexity is the more recent discovery of Neolithic crannogs, which has pushed back the accepted date for these sites by over 3000 years.
In our pursuit to shed light on this newest piece of the enigma, we embarked on a systematic study, departing from the simple replication of existing databases. Instead, we focused on mining and extracting information from articles published in the Proceedings of the Society of Antiquaries of Scotland, which represent a substantial portion of early crannog research. While generating descriptive statistics is useful, true knowledge advancement comes from contextualising the data and the ideologies that shaped their generation. Our meticulous data mining and information extraction analysis allowed us to understand the historiography of Scottish crannogs in new ways. By analysing terminologies used through time, we identified inconsistencies, biases and even geographic discrepancies in site classifications. Through additional refinement of this database and subsequent fieldwork, we were able to identify new, previously unrecorded, sites and question the validity of some ‘known’ sites.
To address ambiguities surrounding island origins and classification inconsistencies, we expanded our focus to include all 'archaeological islands'. This broadened scope has deepened our understanding of site types and their differential visibility in the national heritage record. To avoid interpretative dissonance, future insights must be integrated with national datasets, ensuring that the archaeological record continues to foster innovation and accommodate expanding knowledge