Quantum corrections to the ground state energy of a trapped Bose-Einstein condensate: A diffusion Monte Carlo calculation

The diffusion Monte Carlo method is applied to describe a trapped atomic Bose-Einstein condensate at zero temperature, fully quantum mechanically and nonperturbatively. For low densities, $n(0)a^3 \le 2 \cdot 10^{-3}$ [n(0): peak density, a: s-wave scattering length], our calculations confirm that the exact ground state energy for a sum of two-body interactions depends on only the atomic physics parameter a, and no other details of the two-body model potential. Corrections to the mean-field Gross-Pitaevskii energy range from being essentially negligible to about 20% for N=2-50 particles in the trap with positive s-wave scattering length a=100-10000 a.u.. Our numerical calculations confirm that inclusion of an additional effective potential term in the mean-field equation, which accounts for quantum fluctuations [see e.g. E. Braaten and A. Nieto, Phys. Rev. B 56}, 14745 (1997)], leads to a greatly improved description of trapped Bose gases.Comment: 7 pages, 4 figure

Elementary excitations of trapped Bose gas in the large-gas-parameter regime

We study the effect of going beyond the Gross-Pitaevskii theory on the frequencies of collective oscillations of a trapped Bose gas in the large gas parameter regime. We go beyond the Gross-Pitaevskii regime by including a higher-order term in the interatomic correlation energy. To calculate the frequencies we employ the sum-rule approach of many-body response theory coupled with a variational method for the determination of ground-state properties. We show that going beyond the Gross-Pitaevskii approximation introduces significant corrections to the collective frequencies of the compressional mode.Comment: 17 pages with 4 figures. To be published in Phys. Rev.

Natural Orbitals and BEC in traps, a diffusion Monte Carlo analysis

We investigate the properties of hard core Bosons in harmonic traps over a wide range of densities. Bose-Einstein condensation is formulated using the one-body Density Matrix (OBDM) which is equally valid at low and high densities. The OBDM is calculated using diffusion Monte Carlo methods and it is diagonalized to obtain the "natural" single particle orbitals and their occupation, including the condensate fraction. At low Boson density, $na^3 < 10^{-5}$, where $n = N/V$ and $a$ is the hard core diameter, the condensate is localized at the center of the trap. As $na^3$ increases, the condensate moves to the edges of the trap. At high density it is localized at the edges of the trap. At $na^3 \leq 10^{-4}$ the Gross-Pitaevskii theory of the condensate describes the whole system within 1%. At $na^3 \approx 10^{-3}$ corrections are 3% to the GP energy but 30% to the Bogoliubov prediction of the condensate depletion. At $na^3 \gtrsim 10^{-2}$, mean field theory fails. At $na^3 \gtrsim 0.1$, the Bosons behave more like a liquid $^4$He droplet than a trapped Boson gas.Comment: 13 pages, 14 figures, submitted Phys. Rev.

Geographical and climatic limits of needle types of one- and two-needled pinyon pines

Aim The geographical extent and climatic tolerances of one- and two-needled pinyon pines (Pinus subsect. Cembroides) are the focus of questions in taxonomy, palaeoclimatology and modelling of future distributions. The identification of these pines, traditionally classified by one- versus two-needled fascicles, is complicated by populations with both one- and two-needled fascicles on the same tree, and the description of two more recently described one-needled varieties: the fallax-type and californiarum-type. Because previous studies have suggested correlations between needle anatomy and climate, including anatomical plasticity reflecting annual precipitation, we approached this study at the level of the anatomy of individual pine needles rather than species. Location Western North America. Methods We synthesized available and new data from field and herbarium collections of needles to compile maps of their current distributions across western North America. Annual frequencies of needle types were compared with local precipitation histories for some stands. Historical North American climates were modeled on a c. 1-km grid using monthly temperature and precipitation values. A geospatial model (ClimLim), which analyses the effect of climate modulated physiological and ecosystem processes, was used to rank the importance of seasonal climate variables in limiting the distributions of anatomical needle types. Results The pinyon needles were classified into four distinct types based upon the number of needles per fascicle, needle thickness and the number of stomatal rows and resin canals. The individual needles fit well into four categories of needle types, whereas some trees exhibit a mixture of two needle types. Trees from central Arizona containing a mixture of Pinus edulis and fallax-type needles increased their percentage of fallax-type needles following dry years. All four needle types occupy broader geographical regions with distinctive precipitation regimes. Pinus monophylla and californiarum-type needles occur in regions with high winter precipitation. Pinus edulis and fallax-type needles are found in regions with high monsoon precipitation. Areas supporting californiarum-type and fallax-type needle distributions are additionally characterized by a more extreme May–June drought. Main conclusions These pinyon needle types seem to reflect the amount and seasonality of precipitation. The single needle fascicle characterizing the fallax type may be an adaptation to early summer or periodic drought, while the single needle of Pinus monophylla may be an adaptation to summer–autumn drought. Although the needles fit into four distinct categories, the parent trees are sometimes less easily classified, especially near their ancestral Pleistocene ranges in the Mojave and northern Sonoran deserts. The abundance of trees with both one- and two-needled fascicles in the zones between P. monophylla, P. edulis and fallax-type populations suggest that needle fascicle number is an unreliable characteristic for species classification. Disregarding needle fascicle number, the fallax-type needles are nearly identical to P. edulis, supporting Little’s (1968) initial classification of these trees as P. edulis var. fallax, while the californiarum-type needles have a distinctive morphology supporting Bailey’s (1987) classification of this tree as Pinus californiarum

Lived experiences of the diagnostic assessment process for Fetal Alcohol Spectrum Disorder: A systematic review of qualitative evidence

First published: 02 May 2023Early assessment and diagnosis of FASD are crucial in providing therapeutic interventions that aim to enhance meaningful participation and quality of life for individuals and their families, while reducing psychosocial difficulties that may arise during adolescence and adulthood. Individuals with lived experience of FASD have expertise based on their own lives and family needs. Their insights into the assessment and diagnostic process are valuable for improving service delivery and informing the provision of meaningful, person- and family-centered care. To date, reviews have focused broadly on the experiences of living with FASD. The aim of this systematic review is to synthesize qualitative evidence on the lived experiences of the diagnostic assessment process for FASD. Six electronic databases, including PubMed, the Cochrane Library, CINAH, EMBASE, PsycINFO, and Web of Science Core Collection were searched from inception until February 2021, and updated in December 2022. A manual search of reference lists of included studies identified additional studies for inclusion. The quality of included studies was assessed using the Critical Appraisal Skills Program Checklist for Qualitative Studies. Data from included studies were synthesized using a thematic analysis approach. GRADE-CERQual was used to assess confidence in the review findings. Ten studies met the selection criteria for inclusion in the review. Thematic analysis identified 10 first-level themes relating to four over-arching topics: (1) pre-assessment concerns and challenges, (2) the diagnostic assessment process, (3) receipt of the diagnosis, and (4) post-assessment adaptations and needs. GRADECERQual confidence ratings for each of the review themes were moderate to high. The findings from this review have implications for referral pathways, client-centered assessment processes, and post-diagnostic recommendations and support.Nicole Hayes, Kerryn Bagley, Nicole Hewlett, Elizabeth J. Elliott, Carmela F. Pestell, Matthew J. Gullo, Zachary Munn, Philippa Middleton, Prue Walker, Haydn Till, Dianne C. Shanley, Sophia L. Young, Nirosha Boaden, Delyse Hutchinson, Natalie R. Kippin, Amy Finlay- Jones, Rowena Friend, Doug Shelton, Alison Crichton, Natasha Rei

The ‘mosaic habitat’ concept in human evolution: past and present

The habitats preferred by hominins and other species are an important theme in palaeoanthropology, and the ‘mosaic habitat’ (also referred to as habitat heterogeneity) has been a central concept in this regard for the last four decades. Here we explore the development of this concept – loosely defined as a range of different habitat types, such as woodlands, riverine forest and savannah within a limited spatial area– in studies of human evolution in the last sixty years or so. We outline the key developments that took place before and around the time when the term ‘mosaic’ came to wider palaeoanthropological attention. To achieve this we used an analysis of the published literature, a study of illustrations of hominin evolution from 1925 onwards and an email survey of senior researchers in palaeoanthropology and related fields. We found that the term mosaic starts to be applied in palaeoanthropological thinking during the 1970’s due to the work of a number of researchers, including Karl Butzer and Glynn Isaac , with the earliest usage we have found of ‘mosaic’ in specific reference to hominin habitats being by Adriaan Kortlandt (1972). While we observe a steady increase in the numbers of publications reporting mosaic palaeohabitats, in keeping with the growing interest and specialisation in various methods of palaeoenvironmental reconstruction, we also note that there is a lack of critical studies that define this habitat, or examine the temporal and spatial scales associated with it. The general consensus within the field is that the concept now requires more detailed definition and study to evaluate its role in human evolution

Women’s beliefs about medicines and adherence to pharmacotherapy in pregnancy: Opportunities for community pharmacists?

Background During pregnancy women might weigh benefits of treatment against potential risks to the unborn child. However, non-adherence to necessary treatment can adversely affect both mother and child. To optimize pregnant women’s beliefs and medication adherence, community pharmacists are ideally positioned to play an important role in primary care. Objective This narrative review aimed to summarize the evidence on 1) pregnant women’s beliefs, 2) medication adherence in pregnancy, and 3) community pharmacists’ counselling during pregnancy. Method Three search strategies were used in Medline and Embase to find original studies evaluating women’s beliefs, medication adherence and community pharmacists’ counselling during pregnancy. All original descriptive and analytic epidemiological studies performed in Europe, North America and Australia, written in English and published from 2000 onwards were included. Results We included 14 studies reporting on women’s beliefs, 11 studies on medication adherence and 9 on community pharmacists’ counselling during pregnancy. Women are more reluctant to use medicines during pregnancy and tend to overestimate the teratogenic risk of medicines. Risk perception varies with type of medicine, level of health literacy, education level and occupation. Furthermore, low medication adherence during pregnancy is common. Finally, limited evidence showed current community pharmacists’ counselling is insufficient. Barriers hindering pharmacists are insufficient knowledge and limited access to reliable information. Conclusion Concerns about medication use and non-adherence are widespread among pregnant women. Community pharmacists’ counselling during pregnancy is insufficient. Further education, training and research are required to support community pharmacists in fulfilling all the opportunities they have when counselling pregnant women