‘Are you going to go?’ Putting a pedagogical grammar rule under the corpus spotlight

A rule stating that we tend to avoid using go and come after the future marker going to appears again and again in many coursebooks and grammars used in English Language Teaching, and has done for decades. This article attempts to show, using empirical evidence from corpora, why the rule is inaccurate, and different ways that this might be established. As the rule under consideration is typically framed as a tendency (like many other pedagogical grammar rules), an additional aim of the work is to outline the kinds of corpus analyses researchers and materials designers can potentially use in order to investigate the question of (claimed) linguistic tendencies. The article concludes by discussing why a rule that is apparently inaccurate nevertheless appears again and again in print, arguing that the existence of a well-established and widely-accepted ‘canon’ of ELT grammar means that such inaccuracies in descriptions of grammar can be easily perpetuate

Recruiting hard-to-reach populations to physical activity studies : evidence and experiences

Most researchers who are conducting research with a public health focus face difficulties in recruiting the segments of the population that they really want to reach. This symposium presented evidence and experiences on recruiting participants to physical activity research, including both epidemiological and intervention based studies. Results from a systematic review of recruitment strategies suggested that we know little about how best to recruit and highlighted the need for researchers to report this in more detail, including metrics of reach into the target population such as number, proportion, and representativeness of participants. Specific strategies used to optimise responses to a population-based mail survey were presented such as study promotion, survey design, multiple mailings, and personal engagement. Finally, using place based recruiting via schools or places of worship to target ethnic minority youth were discussed. Overall the symposium presenters suggested that we need to learn more about how best to recruit participants, in particular those typically under-represented, and that researchers need to apportion a similar amount of planning effort to their recruitment strategies as they do the their research design. Finally we made a plea for researchers to report their recruitment processes in detail

The human placenta: new perspectives on its formation and function during early pregnancy

The placenta has evolved to support the development of the embryo and fetus during the different intrauterine periods of life. By necessity, its development must precede that of the embryo. There is now evidence that during embryogenesis and organogenesis, the development of the human placenta is supported by histotrophic nutrition secreted from endometrial glands rather than maternal blood. These secretions provide a plentiful supply of glucose, lipids, glycoproteins and growth factors that stimulate rapid proliferation and differentiation of the villous trophoblast. Furthermore, evidence from endometrial gland organoids indicates that expression and secretion of these products are upregulated following sequential exposure to oestrogen, progesterone and trophoblastic and decidual hormones, in particular prolactin. Hence, a feed-forward signalling dialogue is proposed among the trophoblast, decidua and glands that enables the placenta to stimulate its own development, independent of that of the embryo. Many common complications of pregnancy represent a spectrum of disorders associated with deficient trophoblast proliferation. Increasing evidence suggests that this spectrum is mirrored by one of impaired decidualization, potentially compromising histotroph secretion through diminished prolactin secretion and reduced gland function. Optimizing endometrial wellbeing prior to conception may therefore help to prevent common pregnancy complications, such as miscarriage, growth restriction and pre-eclampsia

Pathophysiology of Placenta Accreta Spectrum Disorders: A Review of Current Findings.

Current findings continue to support the concept of a biologically defective decidua rather than a primarily abnormally invasive trophoblast. Prior cesarean sections increase the risk of placenta previa and both adherent and invasive placenta accreta, suggesting that the endometrial/decidual defect following the iatrogenic creation of a uterine myometrium scar has an adverse effect on early implantation. Preferential attachment of the blastocyst to scar tissue facilitates abnormally deep invasion of trophoblastic cells and interactions with the radial and arcuate arteries. Subsequent high velocity maternal arterial inflow into the placenta creates large lacunae, destroying the normal cotyledonary arrangement of the villi

Development of the Human Placenta and Fetal Heart: Synergic or Independent?

The placenta is the largest fetal organ, and toward the end of pregnancy the umbilical circulation receives at least 40% of the biventricular cardiac output. It is not surprising, therefore, that there are likely to be close haemodynamic links between the development of the placenta and the fetal heart. Development of the placenta is precocious, and in advance of that of the fetus. The placenta undergoes considerable remodeling at the end of the first trimester of pregnancy, and its vasculature is capable of adapting to environmental conditions and to variations in the blood supply received from the mother. There are two components to the placental membranes to consider, the secondary yolk sac and the chorioallantoic placenta. The yolk sac is the first of the extraembryonic membranes to be vascularized, and condensations in the mesenchyme at ~17 days post-conception (p.c.) give rise to endothelial and erythroid precursors. A network of blood vessels is established ~24 days p.c., with the vitelline vein draining through the region of the developing liver into the sinus venosus. Gestational sacs of early pregnancy failures often display aberrant development of the yolk sac, which is likely to be secondary to abnormal fetal development. Vasculogenesis occurs in the villous mesenchyme of the chorioallantoic placenta at a similarly early stage. Nucleated erythrocytes occupy the lumens of the placental capillaries and end-diastolic flow is absent in the umbilical arterial circulation throughout most of the first trimester, indicating a high resistance to blood flow. Resistance begins to fall in the umbilico-placental circulation around 12-14 weeks. During normal early pregnancy the placental capillary network is plastic, and considerable remodeling occurs in response to the local oxygen concentration, and in particular to oxidative stress. In pregnancies complicated by preeclampsia and/or fetal growth restriction, utero-placental malperfusion induces smooth muscle cells surrounding the placental arteries to dedifferentiate and adopt a proliferative phenotype. This change is associated with increased umbilical resistance measured by Doppler ultrasound, and is likely to exert a major effect on the developing heart through the afterload. Thus, both the umbilical and maternal placental circulations may impact on development of the heart

The placenta: a multifaceted, transient organ.

The placenta is arguably the most important organ of the body, but paradoxically the most poorly understood. During its transient existence, it performs actions that are later taken on by diverse separate organs, including the lungs, liver, gut, kidneys and endocrine glands. Its principal function is to supply the fetus, and in particular, the fetal brain, with oxygen and nutrients. The placenta is structurally adapted to achieve this, possessing a large surface area for exchange and a thin interhaemal membrane separating the maternal and fetal circulations. In addition, it adopts other strategies that are key to facilitating transfer, including remodelling of the maternal uterine arteries that supply the placenta to ensure optimal perfusion. Furthermore, placental hormones have profound effects on maternal metabolism, initially building up her energy reserves and then releasing these to support fetal growth in later pregnancy and lactation post-natally. Bipedalism has posed unique haemodynamic challenges to the placental circulation, as pressure applied to the vena cava by the pregnant uterus may compromise venous return to the heart. These challenges, along with the immune interactions involved in maternal arterial remodelling, may explain complications of pregnancy that are almost unique to the human, including pre-eclampsia. Such complications may represent a trade-off against the provision for a large fetal brain.This is the accepted manuscript. It's currently embargoed until 19/01/2016. the final version is available from Royal Society Publishing at http://rstb.royalsocietypublishing.org/content/370/1663/2014006