Who is afraid of constructivism? (¿Quién tiene miedo del constructivismo?)

Both generative and constructivist researchers agree that children are able to form abstractions and produce novel grammatically patterned utterances. Both approaches are able to explain such abilities, and hence their existence does not entail an innate Universal Grammar. However, generativists and constructivists differ in their views on the nature of early generalisations: while generative researchers assume that adult-like linguistic representations are present from the very beginning, constructivists argue that children begin with relatively specific, low level schemas and gradually extract more abstract patterns. There is considerable empirical evidence for the latter position. Moreover, constructivist theories provide a better explanation for principled behaviour -not just the observed patterns, but also the absence of certain constructions in children's early productions and various developmental asynchronies. Tanto los investigadores generativistas como constructivistas coinciden en que los niños son capaces de formar abstracciones y de producir emisiones novedosas gramaticalmente estructuradas. Ambos enfoques son capaces de explicar tales habilidades, y por eso su existencia no implica una Gramática Universal innata. Sin embargo, los investigadores generativistas y constructivistas difieren en su visión sobre la naturaleza de las generalizaciones tempranas: mientras que los investigadores generativistas asumen que las representaciones lingüísticas parecidas a las adultas están presentes desde edades tempranas, los constructivistas argumentan que los niños comienzan con esquemas de bajo nivel, relativamente específicos, y que gradualmente extraen esquemas más abstractos. Existe considerable evidencia empírica en apoyo de esta segunda posición. Además, las teorías constructivistas proporcionan una mejor explicación de las conductas basadas en reglas; no sólo de los patrones observados, sino también de la ausencia de ciertas construcciones en las producciones verbales tempranas de los niños y de diversas asincronías evolutivas

Quantum depletion of collapsing Bose-Einstein condensates

We perform the first numerical three-dimensional studies of quantum field effects in the Bosenova experiment on collapsing condensates by E. Donley et al. [Nature 415, 39 (2002)] using the exact experimental geometry. In a stochastic truncated Wigner simulation of the collapse, the collapse times are larger than the experimentally measured values. We find that a finite temperature initial state leads to an increased creation rate of uncondensed atoms, but not to a reduction of the collapse time. A comparison of the time-dependent Hartree-Fock-Bogoliubov and Wigner methods for the more tractable spherical trap shows excellent agreement between the uncondensed populations. We conclude that the discrepancy between the experimental and theoretical values of the collapse time cannot be explained by Gaussian quantum fluctuations or finite temperature effects.Comment: 9 pages, 4 figures, replaced with published versio

The engagement of young people in drug interventions in coercive contexts: findings from a cross-national European study

Background: The engagement of young people has been a neglected area in youth justice and drugs policy and practice. This paper explores the concept of ‘engagement’ in relation to drugs interventions in custodial and community settings in different European countries. Methods: Interviews were undertaken with young people (aged 14-25 years) in contact with the criminal justice system who use illegal drugs and with practitioners involved in the delivery of interventions for our target group in Denmark, Italy, Poland the UK. Results: The key techniques to engage young people were described in similar terms across the countries. These included forming relationships based on trust, honesty and empathy, setting goals collaboratively and employing practitioners with lived experience and understanding. The objectives and activities on offer are often constrained by the criminal justice contexts. Conclusions: Despite the differences between the countries in terms of criminal justice systems and the structure of drug interventions, there were remarkable similarities in the ways young people and practitioners described effective engagement. Strong emphasis on operational engagement to ensure positive relationships between young people and practitioners was important in the design and delivery of interventions. Practitioners working in criminal justice contexts need to have flexibility and autonomy to work creatively to find ways to engage, connect and inspire young people

Zipf's law in Multifragmentation

We discuss the meaning of Zipf's law in nuclear multifragmentation. We remark that Zipf's law is a consequence of a power law fragment size distribution with exponent $\tau \simeq 2$. We also recall why the presence of such distribution is not a reliable signal of a liquid-gas phase transition

Quantum-field dynamics of expanding and contracting Bose-Einstein condensates

We analyze the dynamics of quantum statistics in a harmonically trapped Bose-Einstein condensate, whose two-body interaction strength is controlled via a Feshbach resonance. From an initially non-interacting coherent state, the quantum field undergoes Kerr squeezing, which can be qualitatively described with a single mode model. To render the effect experimentally accessible, we propose a homodyne scheme, based on two hyperfine components, which converts the quadrature squeezing into number squeezing. The scheme is numerically demonstrated using a two-component Hartree-Fock-Bogoliubov formalism.Comment: 9 pages, 4 figure

Building cultures of participation: involving young people in contact with the criminal justice system in the development of drug interventions in the United Kingdom, Denmark, Italy and Poland

This paper explores the participation of young people in contact with criminal justice systems in the development of drugs interventions. Interviews were undertaken with 160 young people (aged 15-25) and 66 practitioners involved in the design, delivery and commissioning of drug interventions. We analyse the key challenges in involving young people in the development of interventions including structural, organisational and individual factors. We argue that these barriers can be overcome by fostering flexible models of participation and identifying the most meaningful and appropriate approaches for involving young people at different stages and in different initiatives which consider socio-cultural contexts

Cannabinoid receptors expression in bone marrow trephine biopsy of chronic lymphocytic leukaemia patients treated with purine analogues

Background: Cannabinoid receptors CB1 and CB2 are part the endocannabinoid system that plays an important role in the process of proliferation and apoptosis of different neoplastic cells. B-cell chronic lymphocytic leukaemia is one of the diseases in which these processes are altered. Aim: The aim of our study was the assessment of cannabinoid receptor expression on the B-lymphocytes in bone marrow trephine biopsy from leukaemic patients at diagnosis and after purine analogue treatment. Methods: The biopsy was taken routinely and standard immunohistochemical staining procedure for paraffin embedded sections was applied. The cannabinoid receptors were detected using specific primary polyclonal antibody anti-CB1 and anti-CB2. Additionally, an existence of cannabinoid receptors was confirmed by flow cytometry. Results: The results showed that the expression of CB1 receptor on the surface of neoplastic cells was lower than that of CB2 (17.0 ± 3.1% and 92.1 ± 1.7% respectively, p < 0.001). Nine of the patients responded to applied treatment with a reduction in leukaemic infiltration (77.2 ± 6.9% to 30.2 ± 6.5%, p = 0.007) and CB1 receptor expression (24.4 ± 4.8% to 8.6 ± 2.9%, p = 0.01), but there was no change in CB2 expression (91.7 ± 2.7% vs 90.9 ± 2.8%, p = 0.69). Four patients without remission expressed even greater number of the receptors. In all of the cases both cannabinoid receptor types antibodies gave positive reaction. Furthermore, the existence of cannabinoid receptors on neoplastic lymphocytes was confirmed by flow cytometry. Conclusion: The study provides original evidence for the existence of cannabinoid receptors on B-lymphocytes in chronic lymphocytic leukaemia patients. The receptors are thought to be a new structure that can modify the course of the disease and may be considered as a new target in leukaemia treatment.Обоснование: рецепторы каннабиноидов CB1 и CB2 яв ляются частью системы эндоканнабиноидов, которая играет важную роль в процессах пролиферации и апоптоза различных неопластических клеток. Одним из заболеваний, при которых происходит нарушение этих процессов, является В-клеточный хронический лимфлейкоз. Цель: оценка экспрессии рецепторов каннабиноидов на В-лимфоцитах в трепанобиоптатах у больных лейкозом до и после проведения лечения с использованием пуриновых аналогов. Методы: биоптаты получили рутинными методами; иммуногистохимическое исследование депарафинизированных срезов проводили по стандартной процедуре. Рецепторы каннабиноидов определяли с использованием специфических моноклональных антител анти-CB1 и анти-CB2. Кроме того, наличие рецепторов подтверждено при по- мощи проточной цитофлуориметрии. Результаты: показано, что экспрессия рецептора CB1 на поверхности опухолевых клеток ниже, чем экспрессия CB2 (17,0  ± 3,1% и 92,1 1,7% твенно, p < 0,001). После проведенного лечения у 9 пациентов отмечалось уменьшение лейкозного инфильтрата (77,2 6,9% до 30,2 6,5%, p = 0,007) и снижение экспрессии рецептора CB1 (24,4 4,8% до 8,6 2,9%, p = 0,01), однако различий в экспрессии CB2 не отмечали (91,7 2,7% против 90,9 2,8%, p = 0,69). У 4 пациентов, у которых не удалось достичь ремиссии, определяли даже повышение экспрессии рецепторов. Во всех случаях маркировки антителами к обоим типам рецепторов каннабиноидов отмечали поло- жительную реакцию. Более того, присутствие рецепторов каннабиноидов на злокачественных клетках подтверждали при помощи проточной цитометрии. Выводы: в ходе исследования показано изначальное наличие рецепторов каннабиноидов на В-лимфоцитах у больных хроническим лимфолейкозом. Указанные рецепторы могут быть новой структурой, которая может быть модифицирована в течение болезни, и могут считаться новой мишенью при лечении больных лейкозом