We present a mathematical model of a fishery on several sites with a variable price. The model takes into account the evolution during the time of the resource, fish and boat movement between the different sites, fishing effort and price that varies with respect to supply and demand. We suppose that the movements of the boats and resource as well as the variation of the price go on at a fast time scale. We use methods of aggregation of variables in (...) order to reduce the number of variables and we derive a reduced model governing two global variables, respectively the biomass of the resource and the fishing effort of the whole fishery. We look for the existence of equilibria of the aggregated model and perform local stability analysis. Two main cases can occur. The first one corresponds to over-exploitation leading to fish extinction. At extinction, the fishing effort tends to a positive value. The second case corresponds to a durable fishery equilibrium which is globally asymptotically stable. In the later case, we show that there exists a number of fishing sites that optimizes the total catch of the fishery. (shrink)

We present a mathematical bioeconomic model of a fishery with a variable price. The model describes the time evolution of the resource, the fishing effort and the price which is assumed to vary with respect to supply and demand. The supply is the instantaneous catch while the demand function is assumed to be a monotone decreasing function of price. We show that a generic market price equation (MPE) can be derived and has to be solved to calculate non trivial equilibria (...) of the model. This MPE can have 1, 2 or 3 equilibria. We perform the analysis of local and global stability of equilibria. The MPE is extended to two cases: an age-structured fish population and a fishery with storage of the resource. (shrink)

In this paper, we are trying to summarize the peak of achievement of the Arabian logicians of the fifteenth century by making a classification and sketching in familiar terms the conditional and subjunctive syllogisms in Muḥammad Ibn Yusūf al-SSinūsī’s (1426-1490) work, i.e. in his explanation of Kitāb al-Muḫtaşar fī al-Manṭiq of al-Imām Muḥammad Ibn ʿArafa (1316- 1401).

The form of the conditional syllogism resembles that of the categorical syllogism, while its subject matter is at least a conditional premise, but its conclusion is always conditional conjunctive or disjunctive. This mixed structure to which we apply the rules of the categorical syllogism, is a structure of which Aristotle did not have an idea, and which the Stoics did not conceive, and which the non-Arabian logicians did not know until in modern times. But what we have to notice here (...) is the putting of a conditional matter in the form of the categorical syllogism, and it is this kind of hybridization, if we dare to say, which generated this mixed structure which appeared for the first time in the history of logic in the treatise on the logic of Ibn Sina and which can be considered a discovery by this author until proof to the contrary, and that the ancient Arabian logicians have taken the habit of exhibiting in their treatises. (shrink)

This chapter attempts to further the understanding of Sahelo‐Sudanic systems of slavery via enquiries into the daily life of slaves. This work is based on the memories of elders in certain villages within the zone of the ancient state of Kaarta and the buffer zone between it and the state of Segou, an area corresponding to the modern Malian administrative Cercles of Kolokani and Banamba. Temporally, the focus is on the period directly before the colonial era. In particular, the mode (...) of acquisition of slaves and the different types of local slavery are considered. (shrink)

El propósito de este artículo es mostrar que el escrito medieval no posee el mismo estatuto ni los mismos valores que hoy en día y, a partir de ahí, reaccionar ante la oposición entre lo oral y lo escrito que se utiliza a propósito de la literatura árabe en sus comienzos. La tesis propuesta defiende que, hasta la segunda mitad, si no hasta el final del siglo III de la Hégira, los textos de adab, aunque compuestos y producidos por escrito, (...) lo habían sido en la idea de que su circulación, su comunicación y recepción se haría, en la mayor parte de los casos, oralmente. Es este fenómeno el que define el estatus del adab de sus «autores», y de la naturaleza de las obras que lo constituyen. (shrink)

Il s¿agit de poursuivre le travail de relecture du Kiláó al-Buhalá' consmencé dans larticle paru dans le Bulleíin dÉludes Orientales de Damas (LI 1999:"Avarice ou sophistique? Une lecture du Livre des ovares d'al-Gdisig"), travail qui pose que le propos du célébre polygraphe nesí pas tant la critique de lavarice, nu de la gueuserie (lmdya) dans le cas de Halib b. Yazid, que celle du détnumement des discours de leura fnnctions supposées nobles. Dans le récit "autobiographique" el le testament spirituel de (...) Ijálawayh al~MukaddI, ce qui se trouve mimé, parodié pnur étre dénigré, cesí, semble-t-il, la pratique des sermonnaires populaire> (Qu~sás), el, plus généralemení, celle des 'ulamá' qui prétendent éduquer les fonles. Larticle s'attache á analyser les procédés stylistiques et rhétoriques utilisés par al-Óálii~ pour vilipender ces usages dévoyés du discours. (shrink)

The robustness of a system indicates its ability to withstand disturbances while maintaining its properties, performance, and efficiency. There are plenty of studies on the robustness of air transport networks in the literature. However, few works consider its mesoscopic organization. Building on the recently introduced component structure, we explore the impact of targeted attacks on the weighted world air transportation network on its components. Indeed, it contains five local components covering different regions and one global component linking these regions. We (...) investigate targeted attacks based on influential weighted centrality measures. Results show that the local components gradually separate from the world air transportation network as the fraction of removed airports grows. The weighted betweenness attack removes fewer top airports to isolate the regions compared to its alternatives. Furthermore, it is still convenient to travel locally in the separate areas. In contrast, strength and PageRank attacks need to target more airports to split the network. However, they are more disruptive. Indeed, the size of the isolated local components reduces drastically, so it becomes more challenging to travel locally. Looking at the world air transportation network through its component structure reveals a new viewpoint on its resilence. It opens new perspectives to design more efficient attacks. (shrink)

Si les sciences ont incontestablement imposé un modèle de rationalité universelle, il ne s'ensuit pas, comme l'Occident l'a trop facilement cru et fait croire, que la société occidentale elle-même et ses valeurs soient, elles aussi, universelles et puissent servir de normes uniques. La mondialisation actuelle et l'histoire ancienne des hommes manifestent la pluralité des modes socioculturels et des règles éthiques. La Rationalité, qui devrait résulter d'une réelle intersubjectivité, ne peut désormais advenir que par la participation de tous et par une (...) convergence des rationalités jusque-là plurielles. L'Afrique est donc nécessairement incluse dans ce débat pour lequel elle propose des paradigmes universalisables. (shrink)

BackgroundPeople say it is hard to stay truly positive in Lebanon. Studies showed that 63% of Lebanese young adults are highly dissatisfied with their country. In fact, young adults are the most vulnerable population to stressors in Lebanon since their future is at stake and it is their time to shape their lives in a country that cripples them. This study aimed to assess factors associated with positivity among a sample of Lebanese university students despite the various stressors they are (...) facing on top of the economic collapse and the COVID-19 pandemic.MethodsThis cross-sectional study was conducted between November and December 2021. A total of 333 participants was recruited through convenience sampling and snowball technique through several areas in Lebanon’s governorates. A linear regression taking the positivity score as the dependent variable was adopted and all variables that showed a correlation > │0.24│ in absolute value were entered in the final model as independent.ResultsA linear regression taking the positivity score as the dependent variable showed that more positive experiences in life, more flourishing, living in rural area compared to urban, and female gender were significantly associated with more positivity.ConclusionThis study demonstrated that the youth’s positivity is strongly affected by age, gender, residency, and the country they live in that will both directly and indirectly shape their life experiences and their ability to flourish and prosper. Along with all the efforts done to help during this collapse and alleviate the stress that young adults are enduring, follow-up studies are still needed to determine accurate coping techniques that pushes these young adults to think positively in a country where negativity reigns and all else fails. (shrink)

ABSTRACTIn a bilingual educational setting, even when mathematical word problems are presented in one’s first language, students may still perform poorly if cognitive constraints such as working me...

RésuméLe problème de la détermination de la Qibla est l'une des questions cruciales qui se posent à la culture scientifique de l'Islam médiéval; le résoudre correctement nécessite tant des théories mathématiques que des observations. Les mathématiques relèvent de deux chapitres: la trigonométrie plane et la trigonométrie sphérique. L'observation et les instruments d'observation sont indispensables à la détermination des coordonnées géographiques de La Mecque et du lieu donné; ces coordonnées sont en effet les données que l'on entre dans les formules donnant (...) la Qibla. Dans son Almageste, Abū al-Wafāʾ résout brillamment ce problème. Son travail porte tant sur les mathématiques que sur l'observation; il obtient des solutions modernes, adéquates et faciles. En trigonométrie plane, il donne de nouvelles définitions des fonctions trigonométriques, démontre les formules des sinus, donne une approximation de sin 1° grâce à laquelle il construit des tables de sinus et de tangentes d'une grande précision. En trigonométrie sphérique, il démontre quatre nouveaux théorèmes dont la règle des tangentes ; cette règle lui permet de trouver, comme nous le montrerons, des solutions simples au problème de la détermination de la Qibla. En ce qui concerne les observations, il décrit trois instruments utilisés par lui plusieurs années de suite à Bagdad. Cet article, nourri de nombreux textes arabes originaux traduits et commentés, donne une description détaillée, technique et analytique, des méthodes mathématiques d'Abū al-Wafāʾ pour la détermination de la Qibla. (shrink)

In the Greek/Indian period, it is noticeable that different radii were used in connection with the chord. This manner continued in the Indian period with the sine, i.e. different sine tables existed. But throughout the Arabic-Islamic period, there was stability in the radius (for the sine). At the time of al-Batt new terms were introduced, not as functions of angles but as lengths, and again different tables for the same term. Here these terms were not bounded to the circle, and (...) the term miqythe radiusfunctions al-Waf’s time, there was an advancement by introducing the new terms as functions of angles, and they were immediately bounded to the circle, and instead of having two circles in the same figure, a kind of unity appeared, and again there was stability in the value of r, and therefore only one table for each function, and thus the new functions started to appear more abstract than practical as the sine did before, and this unity remained fixed in the modern times. (shrink)

We explore the value of the subjunctive mood as a template for understanding ethical action and the theological ontology that undergirds it. We do this by examining the use of a strange but very precisely used word in the writing of a theologian and minister and poet, Samuel Taylor Coleridge: "silly." We do so in the name of exploring the value of contingency, accidentality and abjection to a general theory of ecological thought.

Background The Regional Committee for Africa of the World Health Organization (WHO) in 2001 expressed concern that some health-related studies undertaken in the Region were not subjected to any form of ethics review. In 2003, the study reported in this paper was conducted to determine which Member country did not have a national research ethics committee (REC) with a view to guiding the WHO Regional Office in developing practical strategies for supporting those countries. Methods This is a descriptive study. The (...) questionnaire was prepared and sent by diplomatic pouch to all the 46 Member States in the WHO African Region, through the WHO country representatives, for facilitation and follow up. The data were entered in Excel spreadsheet and subsequently exported to STATA for analysis. A Chi-Squared test (χ 2) for independence was undertaken to test the relationship between presence/absence of Research Ethics Committee (REC) and selected individual socioeconomic and health variables. Results The main findings were as follows: the response rate was 61% (28/46); 64% (18/28) confirmed the existence of RECs; 36% (10/28) of the respondent countries did not have a REC (although 80% of them reported that they had in place an ad hoc ethical review mechanism); 85% (22/26) of the countries that responded to this question indicated that ethical approval of research proposals was, in principle, required; and although 59% of the countries that had a REC expected it to meet every month, only 44% of them reported that the REC actually met on a monthly basis. In the Chi-Squared test, only the average population in the group of countries with a REC was statistically different (at 5% level of significance) from that of the group of countries without a REC. Conclusion In the current era of globalized biomedical research, good ethics stewardship demands that every country, irrespective of its level of economic development, should have in place a functional research ethics review system in order to protect the dignity, integrity and safety of its citizens who participate in research. (shrink)

The examination of power, space, and identity formation within diasporic literature has garnered significant attention due to the escalating global mobility of migrants across the world. This article studies the complex integration of spatial hierarchy, civil violence, and gendered responses to power representations in Jhumpa Lahiri’s novel, The Lowland (2013). We utilise Henri Lefebvre’s theories to dissect the spatial dynamics of the novel across three dimensions: representations of space and conceived space, spatial practice and perceived space, and representational space and (...) lived space. Lefebvre’s framework is instrumental in understanding how physical and conceptual spaces can simultaneously serve as tools for domination and sites for transformative resistance. The novel weaves distinct spatial realms, such as the exclusive Tolly Club and the diminishing lowland, to symbolise postcolonialism and state control. The findings highlight how conceived space is portrayed as a postcolonial realm marked by violence and gendered spatial injustice, reflecting male dominance and societal norms that suppress female subjectivity. However, the study also reveals that this conformity is not static but showcases the agency of female characters like Gauri and Bijoli in resisting and renegotiating spatial constraints. (shrink)

The ongoing coronavirus disease 2019 (COVID-19) pandemic has quickly swept the globe leaving a devastating trail of lost human lives and leading to a public health and economic crisis. With this in mind, prosociality has been heralded as a potential important factor to overcome the negative effects of the pandemic. As such, in this study, we examined the effectiveness of a brief reflexive writing exercise about recent experiences of gratitude on individuals’ intentions to engage in prosocial behaviors using a sample (...) of 253 participants living in Portugal and 280 participants living in Brazil. Participants were randomly assigned to either a condition in which they were asked to write about recent experiences of gratitude or a control group in which they were asked to write about daily tasks. We predicted that the gratitude intervention would increase state gratitude and, consequently, increase positive affect and empathic concern, and decrease negative affect, leading to increased intentions to engage in prosocial behaviors during the COVID-19 pandemic. A moderated serial–parallel mediation analysis, in which we controlled for gender, age, and level of religiosity, indicated that our manipulation led to increases in state gratitude, which in turn increased positive emotions and empathic concern, leading to increased prosocial intentions in both countries. A content analysis of participants’ responses in the gratitude group revealed that relationships with others and health and well-being were the central themes of their gratitude experiences during the COVID-19 global pandemic. (shrink)

Bangladesh experienced a massive surge in humanitarian crises after the 1971 Liberation War due to the systematic use of violence at both public and private spheres. Fictional accounts of the post-conflict period depict women as subjected to institutionalised sexism and aggravated physical and mental violence. Critical studies on such narratives often reiterate a stereotypical and essentialising discourse surrounding women’s identity, characterising them as helpless and passive victims of discrimination and exploitation. Drawing upon Judith Butler’s notions of precarity and agency, we (...) argue that the Bangladeshi-born British writer Tahmima Anam’s The Good Muslim transcends victimhood narratives by creating a more nuanced image of woman as vulnerable victims and resisting subjects at the same time. The novel is preoccupied with notions of vulnerability, violence, religious zealotry, and family estrangement. The findings reveal that the precariousness of women in the post-war period is caused and aggravated by violence and oppression perpetrated at political, social, and religious spheres. Female characters like Maya and Piya are presented as empowered agents of transformation when it comes to vulnerable situations that render them as insignificant and precarious. The study concludes that the novel contests and alters the stereotypical representations of women embedded in normalising and hegemonic discourses. (shrink)

We investigate whether religion acts as a deterrent to the types of mortgage misrepresentation that played a significant role in the recent housing boom and bust. Using a large sample of mortgages originated from 2000 to 2007, we provide evidence that local religious adherence is associated with a lower likelihood of home appraisal overstatement and owner occupancy misreporting. The evidence on borrower income misrepresentation is mixed. Religiosity does not appear to reduce the incidence of income misrepresentation; however, it seems to (...) restrain the degree to which income is misrepresented. Our results are generally consistent with the hypothesis that religion, as a set of social norms, fosters ethical behavior, and possibly risk aversion, in the mortgage market. (shrink)

This article seeks to illustrate the relevance of social theory for the study and practice of law. As social theory reports on changes that influence societal structures, the question for lawyers is how these changes affect law and what this means for its role and function. To this end, the article draws on Ulrich Beck's theory of the risk society and reflexive modernization to provide the relevant perspective. This theory reports upon and explains the so-called side effects of modernization that (...) take the shape of environmental, industrial and political risks. It is these side effects that constitute the problem in risk society and dealing with them demands a reflexive approach towards modernization. The article seeks to highlight the relevance of this theory for law by placing it in the tradition of social contacts theory. It does so by reformulating the central problem of the risk society and by identifying the main social actors who would be party to a "new" social contract. The article then identifies and formulates the instruments of negotiation, at which point it becomes clear what the role of law may be. It concludes with a tentative indication of what the main terms of the social contract could look like. (shrink)

Complex‐trait genetics has advanced dramatically through methods to estimate the heritability tagged by SNPs, both genome‐wide and in genomic regions of interest such as those defined by functional annotations. The models underlying many of these analyses are inadequate, and consequently many SNP‐heritability results published to date are inaccurate. Here, we review the modelling issues, both for analyses based on individual genotype data and association test statistics, highlighting the role of a low‐dimensional model for the heritability of each SNP. We use (...) state‐of‐art models to present updated results about how heritability is distributed with respect to functional annotations in the human genome, and how it varies with allele frequency, which can reflect purifying selection. Our results give finer detail to the picture that has emerged in recent years of complex trait heritability widely dispersed across the genome. Confounding due to population structure remains a problem that summary statistic analyses cannot reliably overcome. Also see the video abstract here: https://youtu.be/WC2u03V65MQ. (shrink)