Context-dependent Factors Research Articles

Assessing urban recycling in low- and middle-income countries: Building on modernised mixtures

Recycling and valorisation of waste in urban centres in low- and middle-income countries is often misunderstood. Recycling in these countries represents neither the service of removal, nor an activity of “greening” related to ecological modernisation. Recycling is first of all an economic activity of commodities extraction, upgrading, and trading, and as such it provides a livelihood for millions of persons worldwide. Based on evidence of waste management and recycling activities in six urban centres in low- and middle-income countries, this paper explores the contribution of informal sector recycling to recycling and solid waste management. It interprets the variety of urban recycling systems as “modernised mixtures”: the mixing of formal municipal waste removal systems with informal private sector recycling activities. Context-dependent factors determine how this mixture of formal and informal systems looks, and how effective informal recycling in these urban centres is. This approach to analysing existing recycling can contribute to improvement of solid waste management systems through sustainable and fair recycling.

TGFβ signalling: a complex web in cancer progression

The distortion of growth factor signalling is the most important prerequisite in tumour progression. Transforming growth factor-beta (TGFbeta) signalling regulates tumour progression by a tumour cell-autonomous mechanism or through tumour-stroma interaction, and has either a tumour-suppressing or tumour-promoting function depending on cellular context. Such inherent complexity of TGFbeta signalling results in arduous, but promising, assignments for developing therapeutic strategies against malignant tumours. As numerous cellular context-dependent factors tightly maintain the balance of TGFbeta signalling and contribute to the regulation of TGFbeta-induced cell responses, in this Review we discuss how they maintain the balance of TGFbeta signalling and how their collapse leads to tumour progression.

Social- and Behavioral-Specific Genetic Effects on Blood Pressure Traits

Background— Population studies have demonstrated an important role of social, behavioral, and environmental factors in blood pressure (BP) levels. Accounting for the genetic interaction of these factors may help to identify common BP susceptibility alleles. Methods and Results— We studied the interaction of additive genetic effects and behavioral (physical activity, smoking, alcohol use) and socioeconomic (education) factors on BP in ≈3600 American Indian participants of the Strong Heart Family Study, using variance component models. The mean and SD of resting systolic and diastolic BPs were 123�17 and 76�11 mm Hg, respectively. We detected evidence for distinct genetic effects on diastolic BP among ever smokers compared with never smokers ( P =0.01). For alcohol intake, we observed significant genotype-by-environment interactions on diastolic (ρg=0.10, P =0.0003) and on systolic BPs (ρg=0.59, P =0.0008) among current drinkers compared with former or never drinkers. We also detected genotype-by-physical activity interactions on diastolic BP (ρg=0.35, P =0.0004). Finally, there was evidence for distinct genetic effects on diastolic BP among individuals with less than high school education compared with those with 12 or more years of education (ρg=0.41, P =0.02). Conclusions— Our findings suggest that behavioral and socioeconomic factors can modify the genetic effects on BP phenotypes. Accounting for context dependent factors may help us to better understand the complexities of the gene effects on BP and other complex phenotypes with high levels of genetic heterogeneity.

Individual movement behavior, matrix heterogeneity, and the dynamics of spatially structured populations

The dynamics of spatially structured populations is characterized by within- and between-patch processes. The available theory describes the latter with simple distance-dependent functions that depend on landscape properties such as interpatch distance or patch size. Despite its potential role, we lack a good mechanistic understanding of how the movement of individuals between patches affects the dynamics of these populations. We used the theoretical framework provided by movement ecology to make a direct representation of the processes determining how individuals connect local populations in a spatially structured population of Iberian lynx. Interpatch processes depended on the heterogeneity of the matrix where patches are embedded and the parameters defining individual movement behavior. They were also very sensitive to the dynamic demographic variables limiting the time moving, the within-patch dynamics of available settlement sites (both spatiotemporally heterogeneous) and the response of individuals to the perceived risk while moving. These context-dependent dynamic factors are an inherent part of the movement process, producing connectivities and dispersal kernels whose variability is affected by other demographic processes. Mechanistic representations of interpatch movements, such as the one provided by the movement-ecology framework, permit the dynamic interaction of birth-death processes and individual movement behavior, thus improving our understanding of stochastic spatially structured populations.

Distinguishing the Effects of Familiarity, Relatedness, and Color Pattern Rarity on Attractiveness and Measuring Their Effects on Sexual Selection in Guppies (Poecilia reticulata)

Mate choice is often based on multiple signal traits and can be influenced by context-dependent factors. Understanding the importance of these signals and factors can be difficult because they are often correlated and might interact. Here, we experimentally disentangle the effects of familiarity, kinship, pattern rarity, and ornament patterns on mate choice in guppies. We estimate whether these factors alter sexual selection on six phenotypic traits known to influence male attractiveness. Rarity of the male's phenotype is the only context-dependent factor that significantly influenced female mating decisions, with common patterns being least attractive. This preference for rare male patterns is a source of negative frequency-dependent selection that may contribute to maintaining the extreme polymorphism in male guppy coloration. Neither visual familiarity nor relatedness between mating partners had any significant effect on mate choice decisions. There was significant linear and nonlinear sexual selection on ornamental traits, but this was not influenced by the context-dependent measures. Our approach highlights the complexity of female mate choice and sexual selection, as well as the value of combining multifactorial experiments with multivariate selection analyses. Our study shows that both negative frequency-dependent selection and disruptive selection contribute to the maintenance of extreme polymorphism in guppies.

Audio Keywords Discovery for Text-Like Audio Content Analysis and Retrieval

Inspired by classical text document analysis employing the concept of (key) words, this paper presents an unsupervised approach to discover (key) audio elements in general audio documents. The (key) audio elements can be considered the equivalents of the text (key) words, and enable content-based audio analysis and retrieval following the analogy to the proven text analysis theories and methods. Since general audio signals usually show complicated and strongly varying distribution and density in the feature space, we propose an iterative spectral clustering method with context-dependent scaling factors to decompose an audio data stream into audio elements. Using this clustering method, temporal signal segments with similar low-level features are grouped into natural clusters that we adopt as audio elements. To detect those audio elements that are most representative for the semantic content, that is, the key audio elements, two cases are considered. First, if only one audio document is available for analysis, a number of heuristic importance indicators are defined and employed to detect the key audio elements. For the case that multiple audio documents are available, more sophisticated measures for audio element importance, including expected term frequency (ETF), expected inverse document frequency (EIDF), expected term duration (ETD) and expected inverse document duration (EIDD), are proposed. Our experiments showed encouraging results regarding the quality of the obtained (key) audio elements and their potential applicability for content-based audio document analysis and retrieval.

Restoration demography and genetics of plants: when is a translocation successful?

Restorations are complex, often involving restoring ecological processes, vegetation structure, and species’ populations. One component of restorations is translocation of key species. Translocations (introductions, reintroductions, augmentations) are often necessary to recover species diversity and install key species. In this review, I consider the ways translocations have been evaluated at various stages during the process of restoration. Vital rates (survival, growth, fecundity) of propagules (seeds, transplants) are commonly used to evaluate initial success. Transplants usually provide greater initial success than do sown seeds. Beyond initial rates, completion of the life cycle through flowering, fruiting, dispersal and subsequent seedling recruitment is a key benchmark. Modelling population viability of translocated populations is a logical next step and can bring in many powerful inferential tools. Of factors affecting the success of translocations, genetic issues are paramount, as restorationists need to consider inbreeding depression, reproductive viability, local adaptation, and evolutionary potential of translocated populations. The success of translocations is also clearly context-dependent, with herbivory, disturbance, competition and other ecological factors important. Future translocations need to make better use of comparisons with reference populations, a long-term perspective on success and an experimental framework that can provide both practical and basic knowledge. Demographic data collection and analysis in restorations has great potential to elucidate causes of translocation failure and improve the prognosis of future restorations.

A Proposal of a Language-Based Context-Sensitive Programming System

This paper describes a programming system with which even novice users can easily specify complex requests as natural language texts, in other words, write programs in everyday language, to operate computing systems. Based on a study of task specification texts written by non-programmers, the processing model is designed so that implicit and ambiguous information in an input text is detected and transformed into an explicit executable program structure. Context dependency in programming is also considered. Context-dependent factors in the situation of program development and the situation of program execution are considered in text understanding and program execution phases, bridging the gap between these two contexts. We have developed a prototype system that deals with personal email management tasks. In this paper, we explain our processing model, give evaluation results, and discuss our proposal’s effectiveness and projected work.

ORIGINAL RESEARCH: Prevalence and Evaluation of Sexual Health Problems—HSDD in Europe

ABSTRACT Introduction The complex condition of the menopause is experienced by all women going through the physical and emotional changes associated with ovarian sexual hormones loss. It may impact directly on their physical and mental health. Aim The complexity of this condition makes it necessary to accumulate large bodies of data to define the patterns and trends in its evaluable manifestations. To this end, large amounts of data were collected on women from France, Germany, Italy, and the United Kingdom, via the Women's International Survey on Health and Sexuality. Main Outcome Measures The key measures within the survey were the Profile of Female of Sexual Function© (PFSF©) and the Personal Distress Scale© (PDS©). Results The survey yielded 2,467 responders aged between 20 and 70, capturing women with surgical and natural menopausal status and those with premenopausal status. In the four EU countries studied, sexual activity decreases by age. An increase in female sexual dysfunction (FSD), particularly loss of sexual desire, is directly correlated with increasing age. However, the distress associated with loss of sexual desire is inversely correlated with age. Cultural and context-dependent factors modulate the percentage of any FSD in the different European countries. This is exemplified in the significant intercountry variation observed in the percentage of low desire in women aged 20–49, with normal ovarian function. However, when women undergo surgical menopause, with concomitant loss of their sexual hormones, the culture-related differences are blunted. Conclusions The findings of this survey have implications for the understanding of hypoactive sexual desire disorder (HSDD), not only the way it should be assessed in clinical practice, but also the most appropriate means for its treatment. Testosterone deficiency is a significant cause of HSDD, and new therapies have been investigated which offer considerable potential to address this hormonal etiology.

Transplanting Instruments that Work: Four Practical Lessons on Eliminating Erroneous Assumptions

The enlargement of the European Union has triggered the exchange of spatial planning practices between East and West. Particularly on the level of policy instruments, the intervention side of the planning spectrum, Western European experts on spatial planning have been actively exporting their knowledge to the new and candidate member states. This exchange seems logical in the light of the many similarities between the new and the old member states, such as their common history, similar land tenure concepts, spatial characteristics and challenges, and of course the EU context in which governance is embedded. However, there are several pitfalls that may cause the exchange of planning experience to lead to disappointing or even negative results. Four pitfalls are discussed in this article and illustrated with examples from Central European rural development. The first pitfall is the lack of sufficiently clear terminology that frustrates successful export of knowledge. When terms are ill-defined, people may use the same word for very different concepts and consequently, co-operation between countries that may look successful at first may in a later stage be blocked by a serious gap between the perceptions of those involved. Second, the pre-occupation with solutions instead of problem analysis is discussed. In successful export of planning knowledge, the basic question should be one of a strategic nature, namely what is the exact nature of the problem (is it a problem at all?) and what way of intervening may positively change the situation. The third pitfall is the underestimation of the range of context-dependent factors that affect the effectiveness of planning instruments. The article proposes a way of developing appropriate insight into an instrument's context-dependency by clarifying the link between the context and a potentially exportable instrument. The fourth pitfall is the persistent assumption that more recent instruments are better than traditional instruments, with the result that traditional approaches are ignored. It is argued here that instruments do not evolve into ever better instruments, but that they merely change along with the preferences of society.

Analysis in indexing: document and domain centered approaches

The paper discusses the notion of steps in indexing and reveals that the document-centered approach to indexing is prevalent and argues that the document-centered approach is problematic because it blocks out context-dependent factors in the indexing process. A domain-centered approach to indexing is presented as an alternative and the paper discusses how this approach includes a broader range of analyses and how it requires a new set of actions from using this approach; analysis of the domain, users and indexers. The paper concludes that the two-step procedure to indexing is insufficient to explain the indexing process and suggests that the domain-centered approach offers a guide for indexers that can help them manage the complexity of indexing.

Analysis of SP Panel Data for Mode Choice based on the Concept of Relative Utility

We argue that context dependence (CD) affects the temporal change of SP data. To reflect this, we propose a new mode choice (r-RP/SP) model based on relative utility function, which consists of the term of alternative similarity and the term of other context-dependent factors like previous choice results. Throughout an empirical analysis, it is confirmed that, (1) the way of using relative utility to incorporate the influence of the CD is effective, (2) the parameters of relative importance (RI) are variant temporally and affected by the CD, (3) as the number of explanatory variables increases, the parameters of RI fluctuate largely among individuals and over time.

Determination of α-Helix Propensity within the Context of a Folded Protein: Sites 44 and 131 in Bacteriophage T4 Lysozyme

To determine the effects of different amino acids on the structure and stability of an α-helix in the context of a globular protein, all 19 naturally occurring amino acids were substituted for Ser44 in phage T4 lysozyme. A more restricted set of nine replacements was also made for Val131. Ser44 and Val131 are two of a very limited number of possible site in T4 lysozyme that are well within α-helices, are solvent-exposed and relatively free of interactions with neighboring residues, and are not involved in crystal contacts. High resolution structures for the majority of the mutants, some of which crystallized non-isomorphously with wild-type, were determined. With the exception of proline, the amino acid substitutions caused little if any perturbation of the α-helix backbone. Also the β-branched residues Thr, Val and Ile show no indication of either side-chain or backbone distortion. Therefore, other than proline, there is no evidence that differences in helix propensities are associated with different amounts of strain introduced into the helix. For reference, and also to allow estimates of side-chain entropy, a survey was made of side-chain conformations in 100 well-refined protein structures. As noted previously all side-chains within α-helices strongly avoid the g - conformation (χ 1 ∼ 60°). This restricts the β-branched residues Thr, Val and Ile to a single conformer ( g +, χ 1 ∼ -60°). Asp, Asn, Met and Ser within helices also overwhelmingly prefer the g + conformation. For Arg, Cys, Gln, Glu, Leu and Lys the t (χ 1 ∼ 180°) and g + conformers are populated roughly equally. Only the aromatic residues, His, Tyr, Trp and Phe prefer the t conformation. These preferences are the same whether the side-chain is buried or solvent-exposed. In general, the side-chain conformations adopted by the residues substituted at positions 44 and 131 correspond to the most commonly observed conformation for the same amino acid in helices in known protein structures. The changes in protein stability for the replacements at site 131 in general agree well with those at site 44 (correlation γ=0·97), suggesting that these may be representative of substitutions at fully solvent-exposed sites in the middle of α-helices. The free energy values also agree quite well with those observed for equivalent replacements in a number of soluble α-helical model peptides and with data from "host-guest" studies and statistical surveys (γ=0·69 to 0·93). The results suggest that helix propensity scales derived from model peptides can be applicable to proteins, but energy differences due to helix propensity, per se, are small, and can easily be masked by a myriad of context-dependent factors. Estimates based on known protein structures of the contribution of side-chain entropy to α-helix propensity have only modest agreement (γ=0·52) with those determined from Monte Carlo calculations. It is argued that hydrophobic interactions between the side-chain of the amino acid and the backbone of the α-helix are more important in determining α-helix propensity than is side chain entropy.

Definite Descriptions and Context-Dependence

Some recent work in the philosophy of language has rightly emphasized the role which contextual factors play in the use of language. An adequate theory about how language operates, we are told, must distinguish between (a) that which expressions, constructions and sentences carry with them from one context to another and (b) that which is added by a context of utterance. The features which carry from one context to another have been referred to as context-independent factors, and those which are added contextually as contextdependent factors. This distinction is not, of course, a new one; but it is fair to say that it has not always been given its due in discussions of logical form. Notably, it is not given its due in Russell's famous theory of definite descriptions. In this paper I will propose an alternative way of analyzing sentences containing definite descriptions which does do justice to this distinction. Before I present this theory, however, I want to distinguish three things: referring, language, and what I will call the referential link. By referring I mean the identification of some object by a speaker (as a subject for communication). By the link I mean the semantical connection between a token of a singular term (e.g., a proper name or a definite description) and an object which makes the utterance containing that token literally about that object. By language I mean singular terms or sentences containing singular terms. Typically, a speaker refers to an object by producing