978 resultados para Greville Formula


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The mineral arsentsumebite Pb2Cu(AsO4)(SO4)(OH), a copper arsenate-sulfate hydroxide of the brackebuschite group has been characterised by Raman spectroscopy. The brackebuschite mineral group are a series of monoclinic arsenates, phosphates and vanadates of the general formula A2B(XO4)(OH,H2O), where A may be Ba, Ca, Pb, Sr, while B may be Al, Cu2+,Fe2+, Fe3+, Mn2+, Mn3+, Zn and XO4 may be AsO4, PO4, SO4,VO4. Bands are assigned to the stretching and bending modes of SO42- AsO43- and HOAsO3 units. Raman spectroscopy readily distinguishes between the two minerals arsentsumebite and tsumebite. Raman bands attributed to arsenate are not observed in the Raman spectrum of tsumebite. Phosphate bands found in the Raman spectrum of tsumebite are not found in the Raman spectrum of arsentsumebite. Raman spectroscopy readily distinguishes the two minerals tsumebite and arsentsumebite.

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Some minerals are formed which show poorly defined X-ray diffraction patterns. Vibrational spectroscopy offers one of the few methods for the assessment of the structure of the oxyanions in such minerals. Among this group of minerals is mallestigite with formula Pb3Sb5+(SO4)(AsO4)(OH)6•3H2O. The objective of this research is to determine the molecular structure of the mineral mallestigite using vibrational spectroscopy. Raman and infrared bands are attributed to the AsO43- , SO42- and water stretching vibrations. Mallestigite is a mineral formed in ancient waste dumps such as occurs at Mallestiger, Carinthia, Austria and as such is a mineral of archaeological significance.

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Research Question How do women who choose not to breastfeed perceive their healthcare experience? Method This qualitative research study used a phenomenographic approach to explore the healthcare experience of women who do not breastfeed. Seven women were interviewed about their healthcare experience relating to their choice of feeding, approximately four weeks after giving birth. Six conceptions were identified and an outcome space was developed to demonstrate the relationships and meaning of the conceptions in a visual format. Findings There were five unmet needs identified by the participants during this study. These needs included equity, self sufficiency, support, education and the need not to feel pressured. Conclusion Women in this study who chose not to breastfeed identified important areas where they felt that their needs were not met. In keeping with the Code of Ethics for Nurses and Midwives, the identified needs of women who do not breastfeed must be addressed in a caring, compassionate and just manner. The care and education of women who formula feed should be of the highest standard possible, even if the choice not to breastfeed is not the preferred choice of healthcare professionals.

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This paper outlines our literature review background, investigation and practical application utilizing a precise optical survey level and total station technology for a specialist industrial measurement application. The practical part of the project was to measure and check specific critical features of the Industrial JIG assembly table used by the Queensland University of Technology (QUT) Motorsport group. The JIG is used in constructing a new Formula SAE race-car frame each year and is used throughout the racing season to check the production frame for twists, bends and potential stresses. The industrial JIG table required two survey approaches, firstly determination of the overall flatness throughout its’ steel base surface. Secondly was the validation of verticality of the steel uprights used to support and hold the race-car frame in place during construction and checking alignment for key suspension components. In addition the investigation brings realisations that there are far more accurate, efficient and economical technologies to be harnessed in industrial metrology.

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Background: Rapid weight gain in infancy is an important predictor of obesity in later childhood. Our aim was to determine which modifiable variables are associated with rapid weight gain in early life. Methods: Subjects were healthy infants enrolled in NOURISH, a randomised, controlled trial evaluating an intervention to promote positive early feeding practices. This analysis used the birth and baseline data for NOURISH. Birthweight was collected from hospital records and infants were also weighed at baseline assessment when they were aged 4-7 months and before randomisation. Infant feeding practices and demographic variables were collected from the mother using a self administered questionnaire. Rapid weight gain was defined as an increase in weight-for-age Z-score (using WHO standards) above 0.67 SD from birth to baseline assessment, which is interpreted clinically as crossing centile lines on a growth chart. Variables associated with rapid weight gain were evaluated using a multivariable logistic regression model. Results: Complete data were available for 612 infants (88% of the total sample recruited) with a mean (SD) age of 4.3 (1.0) months at baseline assessment. After adjusting for mother's age, smoking in pregnancy, BMI, and education and infant birthweight, age, gender and introduction of solid foods, the only two modifiable factors associated with rapid weight gain to attain statistical significance were formula feeding [OR=1.72 (95%CI 1.01-2.94), P= 0.047] and feeding on schedule [OR=2.29 (95%CI 1.14-4.61), P=0.020]. Male gender and lower birthweight were non-modifiable factors associated with rapid weight gain. Conclusions: This analysis supports the contention that there is an association between formula feeding, feeding to schedule and weight gain in the first months of life. Mechanisms may include the actual content of formula milk (e.g. higher protein intake) or differences in feeding styles, such as feeding to schedule, which increase the risk of overfeeding. Trial Registration: Australian Clinical Trials Registry ACTRN12608000056392

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Shattuckite Cu5(SiO3)4(OH)2 is a copper hydroxy silicate and is commonly known as a ‘healing’ mineral. Three shattuckite mineral samples from three different origins were analysed by Raman spectroscopy. Some Raman bands are common in the spectra of the minerals. Raman bands at around 890, 1058 and 1102 are described as the ν3 –SiO3 antisymmetric stretching vibrations. The Raman band at 670 cm-1 is assigned to the ν4 bending modes of the -SiO3 units and the band at around 785 cm-1is due to Si-O-Si chain stretching mode. Raman (and infrared) spectroscopy proves that water is in the molecular structure of shattuckite; thus the formula is better written as Cu5(SiO3)4(OH)2•xH2O.

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Kinoite Ca2Cu2Si3O10(OH)4 is a mineral named after a Jesuit missionary. Raman and infrared spectroscopy have been used to characterise the structure of the mineral. The Raman spectrum is characterised by an intense sharp band at 847 cm-1 assigned to the ν1 (A1g) symmetric stretching vibration. Intense sharp bands at 951, 994 and 1000 cm-1 are assigned to the ν3 (Eu, A2u, B1g) SiO4 antisymmetric stretching vibrations. Multiple ν2 SiO4 vibrational modes indicate strong distortion of the SiO4 tetrahedra. Multiple CaO and CuO stretching bands are observed. Raman spectroscopy confirmed by infrared spectroscopy clearly shows that hydroxyl units are involved in the kinoite structure. Based upon the infrared spectra, it is proposed that water is also involved in the kinoite structure. Based upon vibrational spectroscopy, the formula of kinoite is defined as Ca2Cu2Si3O10(OH)4•xH2O.

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In “Really Really”, a series of words float through animated star constellations. While apparently drifting aimlessly, the words can be rearranged in numerous ways to recount roughly the same sappy avowal of long-distance love. The many combinations of words, and their predictable associations, call attention to the thresholds of verbal expression. When some sincere words are needed most it seems as if they’ve all been said before. And so, this declaration of love is both enabled and haunted by the tension between sentiment and formula. “Really Really” continues my interests in how meaning is constructed and circulated, and in particular, how common models of communication continue to frame and yet fall short of our personal experiences.

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Introduction: There is emerging evidence that parenting style and early feeding practices are associated with child intake, eating behaviours and weight status. The aim of this cross sectional study was to examine the relationships between general maternal parenting behaviour and feeding practices and beliefs. Methods: Participants were 421 first-time mothers of 9-22 week old healthy term infants (49% male, mean±sd age 19±4 weeks) enrolled in the NOURISH trial. At baseline mothers self-reported their parenting behaviours (self-efficacy, warmth, irritability) and infant-feeding beliefs using questions from the Longitudinal Study of Australian Children and the Infant Feeding Questionnaire (Baughcum, 2001), respectively. Multivariable regression analyses were used with feeding practices (four factors) as the dependent variables, Independent variables were maternal BMI, weight concern, age, education level perception of infant weight status, feeding mode (breast vs formula) and infant gender, age and weight gain z-score. Results: Parenting behaviours partly were associated with feeding beliefs (adjusted R2 =0.21-0.30). Higher maternal parenting self-efficacy was inversely associated with concerns that the baby would become underweight (p=0.006); become overweight (p<0.001); and lack of awareness of infant hunger/satiety cues (p<0.001). Higher maternal irritability was positively associated with lack of awareness of cues (p<0.05). Maternal warmth was not associated with any feeding beliefs. Infant weight- gain (from birth) z-score and age, maternal BMI and education level and mothers’ perception of infant weight status and feeding mode were covariates. Conclusions: These findings suggest strategies to improve early feeding practices need to be address broader parenting approaches, particularly self-efficacy and irritability.

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Introduction: Feeding on demand supports an infant’s innate capacity to respond to hunger and satiety cues and may promote later self-regulation of intake. Our aim was to examine whether feeding style (on demand vs to schedule) is associated with weight gain in early life. Methods: Participants were first-time mothers of healthy term infants enrolled NOURISH, an RCT evaluating an intervention to promote positive early feeding practices. Baseline assessment occurred when infants were aged 2-7 months. Infants able to be categorised clearly as feeding on demand or to schedule (mothers self report) were included in the logistic regression analysis. The model was adjusted for gender, breastfeeding and maternal age, education, BMI. Weight gain was defined as a positive difference in baseline minus birthweight z-scores (WHO standards) which indicated tracking above weight percentile. Results: Data from 356 infants with a mean age of 4.4 (SD 1.0) months were available. Of these, 197 (55%) were fed on demand, 42 (12%) were fed on schedule. There was no statistical association between feeding style and weight gain [OR=0.72 (95%CI 0.35-1.46), P=0.36]. Formula fed infants were three times more likely to be fed on schedule and formula feeding was independently associated with increased weight gain [OR=2.02 (95%CI 1.11-3.66), P=0.021]. Conclusion: In this preliminary analysis the association between feeding style and weight gain did not reach statistical significance, however , the effect size may be clinically relevant and future analysis will include the full study sample (N=698).

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Introduction: Emerging evidence reveals that early feeding practices are associated with child food intake, eating behaviour and weight status. This cross-sectional analysis examined the association between maternal infant feeding practices/beliefs and child weight in Australian infants aged 11-17 months. Methods: Participants were 293 first-time mothers of healthy term infants (144 boys, mean age 14±1 months) enrolled in the NOURISH RCT. Mothers self-reported infant feeding practices and beliefs using the Infant Feeding Questionnaire (Baughcum, 2001). Anthropometric data were also measured at baseline (infants aged 4 months). Multiple regression analysis was used, adjusting for infant age, gender, birth weight, infant feeding mode (breast vs. formula), maternal perceptions of infant weight status, pre-pregnancy weight, weight concern, age and education. Results: The average child weight-for-age z-score (WAZ) was 0.62±0.83 (range:-1.56 to 2.94) and the mean change in WAZ (WAZ change) from 4 to 14 months was 0.62±0.69 (range:-1.50 to 2.76). Feeding practices/beliefs partly explained child WAZ (R2=0.28) and WAZ change (R2=0.13) in the adjusted models. While child weight status at 14 months was inversely associated with responsive feeding (e.g. baby feeds whenever she wants, feeding to stop baby being unsettled) (β=-0.104, p=0.06) and maternal concern about the child becoming underweight (β=-0.224, p<0.001), it was positively associated with mother’s concern about child overweight (β=0.197, p<0.05). Birth weight, infant’s age, maternal weight concern and perceiving her child as overweight were significant covariates. WAZ change was only significantly associated with responsive feeding (β=-0.147, p<0.05). Conclusion: Responsive feeding may be an important strategy to promote healthy child weight.

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The multianion mineral gartrellite PbCu(Fe3+,Cu)(AsO4)2(OH,H2O)2 has been studied by a combination of Raman and infrared spectroscopy. The vibrational spectra of two gartrellite samples from Durango and Ashburton Downs were compared. Gartrellite is one of the tsumcorite mineral group based upon arsenate and sulphate anions. Crystal symmetry is either triclinic in the case of an ordered occupation of two cationic sites, triclinic due to ordering of the H bonds in the case of species with 2 water molecules per formula unit, or monoclinic in the other cases. Characteristic Raman spectra of the minerals enable the assignment of the bands to specific vibrational modes. These spectra are related to the structure of gartrellite. The position of the hydroxyl and water stretching vibrations are related to the strength of the hydrogen bond formed between the OH unit and the AsO4 anion.

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Zeolite N, an EDI type framework structure with ideal chemical formula K12Al10Si10O40Cl2•5H2O, was produced from kaolin between 100oC and 200oC in a continuously stirred reactor using potassic and potassic+sodic liquors containing a range of anions. Reactions using liquors such as KOH, KOH + KX (where X = F, Cl, Br, I, NO3, NO2), K2X (where X=CO3), KOH + NaCl or NaOH + KCl were complete (>95% product) in less than two hours depending on the batch composition and temperature of reaction. With KOH and KCl in the reaction mixture and H2O/Al2O3~49, zeolite N was formed over a range of concentrations (1M < [KOH] < 18M) and reaction times (0.5h < t < 60h). At higher temperatures or higher KOH molarity, other potassic phases such as kalsilite or kaliophyllite formed. In general, temperature and KOH molarity defined the extent of zeolite N formation under these conditions. The introduction of sodic reagents to the starting mixture or use of one potassic reagent in the starting mixture reduced the stability field for zeolite N formation. Zeolite N was also formed using zeolite 4A as a source of Al and Si albeit for longer reaction times at a particular temperature when compared with kaolin as the source material.

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Whelanite Ca5Cu2(OH)2CO3,Si6O17•4H2O is a hydrated hydroxy mixed anion compound with both silicate and carbonate anions in the formula. The structural characterisation of the mineral whelanite remains incomplete. Whelanite is probably a neosilicate with Cu2+ in square planar coordination. Two Raman bands at 1070 and 1094 cm-1 are assigned to the ν1 symmetric stretching modes of the CO32- units. The observation of two symmetric stretching modes supports the concept of two non-equivalent CO32- units in the whelanite structure. The intense sharp Raman band at 1006 cm-1 is assigned to the ν1 (A1g) symmetric stretching vibration of the Si6O17 units. The splitting of the ν3 vibrational mode offers support to the concept that the SiO4 tetrahedron in whelanite is strongly distorted. A very intense Raman band observed at 666 cm-1 with a shoulder at 697 cm-1 is assigned to the ν4 vibrational modes. Intense Raman bands at 3534, 3556, 3550 and 3595 cm-1 are assigned to the stretching vibrations of the OH units. Low intensity Raman bands at 2910, 3187 and 3453 cm-1 are assigned to water stretching modes. Thus, vibrational spectroscopy has been used to characterise the molecular structure of whelanite. Whelanite is a mineral that could be conceived as a healing mineral

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Purpose: James Clerk Maxwell is usually recognized as being the first, in 1854, to consider using inhomogeneous media in optical systems. However, some fifty years earlier Thomas Young, stimulated by his interest in the optics of the eye and accommodation, had already modeled some applications of gradient-index optics. These applications included using an axial gradient to provide spherical aberration-free optics and a spherical gradient to describe the optics of the atmosphere and the eye lens. We evaluated Young’s contributions. Method: We attempted to derive Young’s equations for axial and spherical refractive index gradients. Raytracing was used to confirm accuracy of formula. Results: We did not confirm Young’s equation for the axial gradient to provide aberration-free optics, but derived a slightly different equation. We confirmed the correctness of his equations for deviation of rays in a spherical gradient index and for the focal length of a lens with a nucleus of fixed index surrounded by a cortex of reducing index towards the edge. Young claimed that the equation for focal length applied to a lens with part of the constant index nucleus of the sphere removed, such that the loss of focal length was a quarter of the thickness removed, but this is not strictly correct. Conclusion: Young’s theoretical work in gradient-index optics received no acknowledgement from either his contemporaries or later authors. While his model of the eye lens is not an accurate physiological description of the human lens, with the index reducing least quickly at the edge, it represented a bold attempt to approximate the characteristics of the lens. Thomas Young’s work deserves wider recognition.