1,174 research outputs found

    Analytical ground state for the three-band Hubbard model

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    For the calculation of charge excitations as those observed in, e.g., photo-emission spectroscopy or in electron-energy loss spectroscopy, a correct description of ground-state charge properties is essential. In strongly correlated systems like the undoped cuprates this is a highly non-trivial problem. In this paper we derive a non-perturbative analytical approximation for the ground state of the three-band Hubbard model on an infinite, half filled CuO_2 plane. By comparison with Projector Quantum Monte Carlo calculations it is shown that the resulting expressions correctly describe the charge properties of the ground state. Relations to other approaches are discussed. The analytical ground state preserves size consistency and can be generalized for other geometries, while still being both easy to interpret and to evaluate.Comment: REVTeX, 8 pages, 6 figures, to appear in Phys. Rev.

    THE DECISION MAKING PROCESS ABOUT TREATMENT FOR INDIGENOUS WOMEN WITH BREAST CANCER FROM THE CANADIAN PRAIRIES

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    This qualitative study focuses on the decision-making process that Indigenous women undergo when receiving breast cancer treatment. The main research question is: how do Indigenous women with breast cancer make decisions around cancer treatment? One-on-one, open-ended interviews were completed with 12 Indigenous women from the Saskatchewan region. A lens of two-eyed seeing was applied, which means that participants were expected to view their life from a traditional or western perspective, or a combination of the two. Four main themes were identified: socioeconomic status, accessibility, culture, cultural safety, and led to women-informed recommendations. Socioeconomic status had three main subthemes of everyday responsibilities, poverty, and medical accessories. Accessibility included three subthemes of knowledge, location, and travel. Culture consisted of two main themes of diversity and stigmas around the disease, with diversity including traditional, western, and two-eyed seeing and stigmas around the disease being mostly related to silence around cancer. Cultural safety included influences from the Indian Residential Schools, feeling like a stranger in the healthcare setting, communication, time, connecting, and self-efficacy. Women-informed recommendations are based on suggestions the women gave regarding aspects related to their treatment choices that they would have liked to have been done differently. The findings from this study will be used in the future for knowledge dissemination, transference, and application

    Challenges of breastfeeding preterm infants: A case study. What goes right, what goes wrong, and what can nurses do?

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    Promoting breastfeeding of preterm infants offers clinical challenges for maternal-child nurses, and requires understanding the experience of the mother. Maternal-child nurses, in collaboration with hospital- and community-based lactation specialists, can meet the unique needs of preterm infants and their mothers. There are several opportunities for nurses to educate other health care professionals in the care of preterm infants and their mothers. The case study in this article presents one mother’s experience of delivering a preterm infant and the many obstacles to breastfeeding that she encountered, and it also offers suggestions for what nurses and other health care professionals can do to make sure other mothers have a more positive experience

    Definitions of severity in treatment seeking studies of febrile illness in children in low and middle income countries: a scoping review

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    Objectives: Understanding treatment seeking for severe febrile illness (SFI) is methodologically challenging. In this scoping review, we investigate definitions of severe febrile illness in treatment seeking studies on children under 5 years of age in low and middle income countries. We analyze the association of SFI definitions with different concepts of treatment seeking and identify related research gaps. Methods: We searched Pubmed, Scopus and WHOLIS, and screened references of included publications for eligibility. Results: Definitions of SFI had either a biomedical perspective (predominantly in quantitative studies) or a caregiver perspective (predominantly in qualitative studies). In quantitative analyses of treatment seeking, severity was more often conceptualized as a determinant rather than an outcome of a treatment seeking process. The majority of quantitative analyses only included surviving children or did not explicitly mention dead children. Conclusion: Different research questions lead to diverse definitions and concepts of severity and treatment seeking outcomes, which limits the comparability of the available evidence. Systematic exclusion of dead children is likely to bias inferences on the association of treatment seeking and health outcomes of children with SFI in low and middle income countries

    Hyperlactation - How left-brained \u27rules\u27 for breastfeeding wreak havoc with a natural process

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    A variety of arbitrary and often unphysiological rules for breastfeeding are frequently suggested to breastfeeding mothers. Many of these rules duplicate strategies commonly used to increase milk supply, and thus, when undertaken by the many women who already have a generous milk supply, can lead to overproduction. Oversupply, or hyperlactation, is a frequent yet often unrecognized problem that can present with a variety of distressing symptoms for the breastfeeding mother and her infant. Infants may present with symptoms suggesting colic, milk protein allergies, or gastroesophageal reflux, or may present with unusually rapid or slow growth. Mothers may present with tender leaking breasts, sore infected nipples, plugged ducts or mastitis, or even the perception of insufficient milk supply. With an understanding of the pathophysiology of these symptoms, proper diagnosis and breastfeeding management can allow milk production to return to homeostatic levels and provide dramatic symptom relief. March 23, 2012: Author’s note 7 years after publication: Over the 7 years since we wrote this manuscript, we continue to see mothers and babies with these same clinical problems, and we are still learning. Here’s a quick look from 2012 at what we wrote in 2005. Specifics can be found in a link at this site soon. During the last 7 years our treatment strategies have become much more simple and flexible since our earlier strategies encouraged too much of the rigid and rule-based left-brained thinking that often causes or contributes to hyperlactation. In this manuscript, we never once mentioned using hands on the breasts as a strategy for preventing or resolving the problems of hyperlactation, and yet in recent years we’ve found this has revolutionized our management approach. We’ve found that when dealing with hyperlactation, pumping can often be counterproductive. Underweight slow weight gain babies are in a category of their own. Regardless of their symptoms, by definition the underweight baby is NOT drinking too much, and in our experience, typical strategies for addressing hyperlactation can be counterproductive or even dangerous. In particular, staying on one side “to get to the hindmilk” doesn’t work with these sleepy, flow-dependent babies. Side switching may be helpful, but is rarely sufficient, and medical attention is critical. While hyperlactation appears to be increasingly recognized by lactation professionals, left-brained strategies abound, and resolution is often elusive, even by those who correctly identify it. Much more research is needed in all of these areas, as well as in several interesting and related areas discussed in our longer note. Finally, the thoughts and suggestions given here cannot replace appropriate medical attention by a physician or other medical provider. We do not encourage self-treatment, particularly when symptoms are severe. Readers seeking lactation support can locate an International Board Certified Lactation Consultant (IBCLC) in their geographic area at www.ilca.org “Find a Lactation Consultant” http://www.ilca.org/i4a/pages/index.cfm?pageid=343

    The goitre rate, its association with reproductive failure, and the knowledge of iodine deficiency disorders (IDD) among women in Ethiopia: Cross-section community based study

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    <p>Abstract</p> <p>Background</p> <p>Iodine deficiency is severe public health problem in Ethiopia. Although urinary iodine excretion level (UIE) is a better indicator for IDD the goitre rate is commonly used to mark the public health significance. The range of ill effect of IDD is however beyond goitre in Ethiopia. In this study the prevalence of goitre and its association with reproductive failure, and the knowledge of women on Iodine Deficiency were investigated.</p> <p>Methods</p> <p>A cross-section community based study was conducted during February to May 2005 in 10998 women in child bearing age of 15 to 49 years. To assess the state of iodine deficiency in Ethiopia, a multistage "Proportional to Population Size" (PPS) sampling methods was used, and WHO/UNICEF/ICCIDD recommended method for goitre classification.</p> <p>Results</p> <p>Total goitre prevalence (weighted) was 35.8% (95% CI 34.5–37.1), 24.3% palpable and 11.5% visible goitre. This demonstrates that more than 6 million women were affected by goitre.</p> <p>Goitre prevalence in four regional states namely Southern Nation Nationalities and People (SNNP), Oromia, Bebshandul-Gumuz and Tigray was greater than 30%, an indication of severe iodine deficiency. In the rest of the regions except Gambella, the IDD situation was mild to moderate. According to WHO/UNICEF/ICCIDD this is a lucid indication that IDD is a major public health problem in Ethiopia. Women with goitre experience more pregnancy failure (X<sup>2 </sup>= 16.5, p < 0.001; OR = 1.26, 1.12 < OR < 1.41) than non goitrous women. Similarly reproductive failure in high goitre endemic areas was significantly higher (X<sup>2 </sup>= 67.52; p < 0.001) than in low. More than 90% of child bearing age women didn't know the cause of iodine deficiency and the importance of iodated salt.</p> <p>Conclusion</p> <p>Ethiopia is at risk of iodine deficiency disorders. The findings presented in this report emphasis on a sustainable iodine intervention program targeted at population particularly reproductive age women. Nutrition education along with Universal Salt Iodization program and iodized oil capsule distribution in some peripheries where iodine deficiency is severe is urgently required.</p

    A review of malaria epidemiology and control in Papua New Guinea 1900 to 2021: progress made and future directions

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    The research and control of malaria has a long history in Papua New Guinea, sometimes resulting in substantial changes to the distribution of infection and transmission dynamics in the country. There have been four major periods of malaria control in PNG, with the current control programme having commenced in 2004. Each previous control programme was successful in reducing malaria burden in the country, but multiple factors led to programme failures and eventual breakdown. A comprehensive review of the literature dating from 1900 to 2021 was undertaken to summarize control strategies, epidemiology, vector ecology and environmental drivers of malaria transmission in PNG. Evaluations of historical control programs reveal poor planning and communication, and di culty in sustaining financial investment once malaria burden had decreased as common themes in the breakdown of previous programs. Success of current and future malaria control programs in PNG is contingent on adequate planning and management of control programs, effective communication and engagement with at-risk populations, and cohesive targeted approaches to sub-national and national control and elimination

    Мероприятия по уменьшению потерь при транспортировке природного газа

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    В газораспределительной сети имеют место производственно-технологические потери природного газа, как нормированные, так и сверхнормативные. В связи с развитием газификации (увеличением протяженности газопроводов, ростом количества газифицированных квартир, объектов и т.д.), старением газопроводов и изношенностью оборудования нормированные потери газа в газораспределительных сетях немного повысятся и к 2030 году составят около 2% от объёмов потребления. Ожидается, что потери природного газа в газотранспортной системе в 2030 году достигнут уровня 0,3% от объёмов его транспортировки. В работе рассмотрены виды и источники технологических потерь природного газа, изучены способы их уменьшения при транспортировке по магистральным газопроводам.In gas-distributing network there can be normalized and above-standard production and technological losses of natural gas. Due to the development of gasification (the extension of gas pipelines, a growing number of gasified apartments, facilities, etc.), ageing of gas pipelines and the depreciation of equipment normalized-losses of gas in gas distribution networks will increase slightly in 2030 will be about 2% of the volume of consumption. It is expected that losses of natural gas in the transmission system in 2030 will reach the level of 0.3% of total transport. The article discusses the types and sources of technological losses of natural gas, studied ways to reduce them during transportation through trunk gas pipelines

    Daily timing of low tide drives seasonality in intertidal emersion mortality risk

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    Sea level exerts a fundamental influence on the intertidal zone, where organisms are subject to immersion and emersion at varying timescales and frequencies. While emersed, intertidal organisms are exposed to atmospheric stressors which show marked diurnal and seasonal variability, therefore the daily and seasonal timing of low water is a key determinant of survival and growth in this zone. Using the example of shallow coral reefs, the coincidence of emersion with selected stressors was investigated for eight locations around the Australian coastline. Hourly water levels (1992 – 2016) from a high-resolution sea level hindcast (http://sealevelx.ems.uwa.edu.au), were linked to maximum surface solar radiation data from the Copernicus ERA5 atmospheric model and minimum atmospheric temperature observations from the Australian Bureau of Meteorology to identify seasonal patterns and historical occurrence of coral emersion mortality risk. Local tidal characteristics were found to dictate the time of day when low water, and therefore emersion mortality risk occurs, varying on a seasonal and regional basis. In general, risk was found to be greatest during the Austral spring when mean sea levels are lowest and a phase change in solar tidal constituents occurs. For all Great Barrier Reef sites, low tide occurs close to midday during winter and midnight in the summer, which may be fundamental factor supporting the historical bio-geographical development of the reef. Interannual variability in emersion mortality risk was mostly driven by non-tidal factors, particularly along the West Coast where El Niño events are associated with lower mean sea levels. This paper highlights the importance of considering emersion history when assessing intertidal environments, including shallow coral reef platform habitats, where critical low water events intrinsically influence coral health and cover. The study addresses a fundamental knowledge gap in both the field of water level science and intertidal biology in relation to the daily timing of low tide, which varies predictably on a seasonal and regional basis
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