To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
A secular trend in body height has been experienced in many nations and populations, hypothesized to be the result of better living conditions. Educational level has been shown to be closely associated with body height. This study examined the changes in body height and popliteal height in a group of adult Chilean male workers by age cohort and the relationship of these with educational level. The body heights and popliteal heights of 1404 male workers from the Valparaíso and Metropolitan regions of Chile were measured in 2016. The sample was grouped by level of education (primary, secondary, technical and university) and age (21–30, 31–40 and 41–50 years). Robust ANOVA and post-hoc analyses using a one-step modified M-estimation of location were conducted based on bootstrap resampling. Both body height and popliteal height increased from the older to the younger age cohort. The largest increase was from the 41–50 to the 21–30 group, with a 1.1% increase in body height and 1.7% increase in popliteal height. When educational level was introduced into the analysis there was a marked increase in both body height and popliteal height for each cohort, but only in primary- and secondary-educated workers. Despite showing an overall increase in body height and popliteal height, younger workers with the highest levels of education showed fewer differences between them than did older workers with less education. The differences were larger in the older than in the younger cohorts. Similarly, this trend was less clear in workers with higher levels of education (technical and university), probably because of a dilution effect caused by increased access to higher education by workers in the lower income quintiles.
To assess the validity of self-reported height and weight by parents of 4-year-old children and subjective weight perception.
Descriptive cross-sectional study.
Paediatric population living in the Autonomous Community of Madrid.
Children born in 2008–2009 examined at 47–59 months of age. Data were collected by paediatricians of the Madrid Primary Care Physicians Sentinel Network. Parents reported weight and height data. Prevalence of weight status categories was calculated using WHO and International Obesity Task Force (IOTF) reference criteria. Sensitivity, specificity and positive predictive value (PPV) were estimated. The appraisal of their child’s weight perception and parental misperception were assessed.
For 2914 children, reported height was underestimated by −1·38 cm, weight by −0·25 kg and BMI was overestimated by +0·41 kg/m2 on average. The prevalence of obesity estimated with reported data was 2·7 times higher than that calculated with measured data (16·2 v. 6·0 %) according to WHO classification, and 3·6 times higher with IOTF classification. Sensitivity to identify obesity was 70·5 %, specificity was 87·3 % and PPV was 26·2 % (WHO classification). Half of the parents of pre-schoolers with obesity failed to identify their child’s weight status. Parental misperception among children classified as having overweight or obesity reached 93·0 and 58·8 %, respectively.
Parents underestimated children’s height and weight, leading to an overestimation of the prevalence of obesity. Small inaccuracies in reported measures have an important effect for the estimation of population prevalences. Parents’ report of child weight status is unreliable. Parental awareness and acknowledgement of child weight status should be improved.
The authors prepared a micro-structured, thermosensitive hydrogel with N-isopropylacrylamide microgels with a lower critical solution temperature (LCST) of 32 °C dispersed on a matrix of N-isopropylacrylamide-co-dimethylacrylamide with an LCST at 40 °C. Incubation of the hydrogel at 33 °C in a solution of fluorescein-albumin induced loading of the protein. The protein was not loaded at a temperature below the LCST of the microgels (4 °C), suggesting that the shrinkage of the microgels followed by the formation of micropores within the hydrogel matrix is a prerequisite for protein loading. A sustained and complete release of the loaded protein was obtained at 37 °C.
More than a decade after fast x-ray transients with an OB supergiant counterpart were identified as a distinct class of wind-accreting sources, we still have not reached a consensus on the physical origin of their similarities and differences with persistent sources. Both kinds seem to extend over the same range of every relevant parameter. Here I argue that, despite this overall overlap, persistent sources have – on average – later-type, more evolved counterparts, and discuss the hypothesis that SFXTs are – on average – a younger population, as well as some of its possible implications.
The complex morphological evolution of the bivalve Ptychomya throughout the well-studied Agrio Formation in the Neuquén Basin (west-central Argentina, lower/upper Valanginian–lowest Barremian) constitutes an ideal opportunity to study evolutionary patterns and processes occurring at geological timescales. Ptychomya is represented in this unit by four species, the morphological variation of which needs to be temporally assessed to obtain a thorough picture of the evolution of the group. Here we use geometric morphometrics to measure variation in shell outline, ribbing pattern, and shell size in these species. We bracket the ages of our samples using a combination of ammonoid biostratigraphy and absolute ages and study the anagenetic pattern of evolution of each trait by means of paleontological time-series analysis and change tracking. We find that evolution in Ptychomya is mostly speciational, as the majority of traits show stasis, with the exceptions of shell size in P. coihuicoensis and shell outline in P. windhauseni, which seem to evolve directionally toward larger and higher shells, respectively. Ptychomya displays changes in its average morphology and disparity, which are the result of a mixture of taxonomic turnover and mosaic evolution of traits. Pulses of speciation would have been triggered by ecological opportunity, as they occur during the recovery of shallow-burrowing bivalve faunas after dysoxic events affecting the basin. On the other hand, the presence of directional patterns of evolution in P. coihuicoensis and P. windhauseni seems to be the result of a general shallowing-upward trend observed in the basin during the upper Hauterivian–lowest Barremian, as opposed to the cyclical paleoenvironmental stability inferred for the early/late Valanginian–early Hauterivian, which would have prompted stasis in P. koeneni and P. esbelta.
A History of Mexican Literature chronicles a story more than five hundred years in the making, looking at the development of literary culture in Mexico from its indigenous beginnings to the twenty-first century. Featuring a comprehensive introduction that charts the development of a complex canon, this History includes extensive essays that illuminate the cultural and political intricacies of Mexican literature. Organized thematically, these essays survey the multilayered verse and fiction of such diverse writers as Sor Juana Inés de la Cruz, Mariano Azuela, Xavier Villaurrutia, and Octavio Paz. Written by a host of leading scholars, this History also devotes special attention to the lasting significance of colonialism and multiculturalism in Mexican literature. This book is of pivotal importance to the development of Mexican writing and will serve as an invaluable reference for specialists and students alike.
Over the past fifteen years, the field of Mexican literary and cultural studies has grown and evolved considerably in the English-language academy. Although the shared border between Mexico and the United States has always precipitated cultural exchange and academic interest, the study of Mexican literature was for many years eclipsed by Chicano studies or by the dominant interest in the Southern Cone within Latin American letters. In the past decade and a half, however, a new generation of scholars of Mexican literature and culture has achieved tenure-line positions in universities in the United States and Canada, most tellingly at institutions where the field had not previously been represented. This is also the case in Great Britain, where scholars of Mexican literature are found not only at flagship institutions such as Cambridge and Oxford, but also, and increasingly, at universities from Sussex to Ulster. The number of graduate students pursuing doctoral work in Mexican literature has increased exponentially, and the quantity and variety of courses on Mexico aimed at undergraduates has grown correspondingly. The field has become so active that Mexican literature is the sole subject of three yearly conferences in the United States (University of California-Santa Barbara, University of Texas at El Paso, and University of California-Irvine). The Modern Language Association has a stand-alone discussion group on Mexican literature with nearly two hundred members, and the Mexico section of the Latin American Studies Association is currently the largest entity within the institution, due to the significant membership of literary scholars. This has tendered an interest in the study of Mexico, one separate from the continental Latin American perspective, as new scholarship has emphasized many specific traits and cultural processes that distinguish Mexico from the rest of the Spanish-speaking world. These include the nature of its indigenous cultures; the status of Mexico City as a viceregal capital during the colonial period; the early triumph of liberalism in the cultural field of the nineteenth century; the experience of the French and U.S. invasions; the Mexican Revolution; and, perhaps most notably of all, the two periods (the Porfiriato and the PRI regime) that established unparalleled, decades-long intervals of stability that in turn allowed for the construction of unusually institutionalized structures of national literature.
In the context of a book such as A History of Mexican Literature, the discussion and selection of works from a literary period in progress is, at the very least, a problematic endeavor. It is always possible that the most recognized works of the contemporary epoch will slowly slide into oblivion – or that the masterworks that capture the present in all its intensity are being written unbeknownst to literary critics. Mexican literature of the neoliberal era, which roughly starts with the cultural policies of the administration of Carlos Salinas de Gortari (1988–1994) and continues to this day, is still a work in progress. To account for it, one must mainly focus on the processes that have defined literature as a set of institutional undertakings that differ in fundamental ways from the postrevolutionary period covered in the other articles in this section, as well as on the aesthetic, ideological, and cultural consequences of these endeavors in works currently considered significant. Some of the phenomena that unfold throughout the 1990s include: the emergence of the Consejo Nacional para la Cultura y las Artes (Conaculta) and its impact on funding for writers; the corporate consolidation of the editorial world and the emergence of independent publishers against the grain of corporatization; the decentralization of literary writing away from the institutions of Mexico City; and the emergence, in particular, of a strong current of writing in northern Mexico and the changes brought forward by the Internet in contemporary writing.
Conaculta is an institutional body of the Mexican government that concentrates the financing and promotion of a large percentage of artistic and cultural production in Mexico. It was created in 1988 in order to coordinate cultural activities of the federal government, and it exists as a “decentralized” organism under the purview of the Secretaría de Educación Pública (SEP). As far as literature is concerned, Conaculta has developed substantial efforts in different parts of the process. Through its fellowship arm, the Fondo Nacional para la Cultura y las Artes (FONCA), it sustains an extensive system of fellowships devoted to the financing of literary artists, ranging from new writers under the age of thirty-five (called Jóvenes Creadores) to authors with a substantial career (in the Sistema Nacional de Creadores Artísticos, under which writers may even get a lifetime fellowship).
Understanding the evolution of a Bauplan starts with discriminating phylogenetic signal from adaptation and the latter from exaptation in the observed biodiversity. Whether traits have predated, accompanied, or followed evolution of particular functions is the basic inference to establish the type of explanations required to determine morphological evolution. To accomplish this, we focus in a particular group of vertebrates, the anurans. Frogs and toads have a unique Bauplan among vertebrates, with a set of postcranial features that have been considered adaptations to jumping locomotion since their evolutionary origin. This interpretation is frequently stated but rarely tested in scientific literature. We test this assumption reconstructing the locomotor capabilities of the earliest known salientian, Triadobatrachus massinoti. This extinct taxon exhibits a mosaic of features that have traditionally been considered as representing an intermediate stage in the evolution of the anuran Bauplan, some of which were also linked to jumping skills. We considered T. massinoti in an explicit evolutionary framework by means of multivariate analyses and comparative phylogenetic methods. We used length measurements of major limb bones of 188 extant limbed amphibians (frogs and salamanders) and lizards as a morphological proxy of observed locomotor behavior. Our findings show that limb data correlate with locomotion, regardless of phylogenetic relatedness, and indicate that salamander-like lateral undulatory movements were the main mode of locomotion of T. massinoti. These results contrast with recent hypotheses and indicate that derived postcranial features that T. massinoti shared with anurans might have been later co-opted as exaptations in jumping frogs.
When high strength and high ductility are required, the Twinning Induced Plasticity steels are an excellent choice. Their mechanical advantages are perfectly known in the automotive industry. Then, they are currently deeply studied. During the deformation at high temperature, TWIP steel experiences dynamic recrystallization. This mechanism results from dislocation interactions, and it depends of temperature, stress, strain, and strain rate. Experimental data give the maximum stress reached by the material, but the critical stress which determinates the DRX onset must be calculated from the strain hardening rate. Both stress and strain change simultaneously, and this variation gives the analytic data to determine σc, which is located at the inflection point of θ-σ plot. The main purpose of this paper was to study how the chemical composition and the experimental parameters (temperature and strain rate) affect the DRX, by the calculation and analysis of the σc values. Hot compression tests were applied to a pair of TWIP steels to compare the DRX onset and its relationship with the vanadium addition. The experimental variables were temperature and strain rate. The true stress–true strain plots were used to calculate σc by cutting data up to a previous point before the σp value, then, a polynomial fit and derivation were applied. The Zener-Hollomon parameter (Z) versus the stresses (peak and critical) plots show how the micro-alloying element vanadium improves the strain hardening in the analyzed TWIP steels.