1,435 research outputs found

    Juvenile/Mature Wood Transition in Loblolly Pine as Defined by Annual Ring Specific Gravity, Proportion of Latewood, and Microfibril Angle

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    The length of juvenility or number of years a tree produces juvenile wood at a fixed height can be defined by the age of the wood at which properties change from juvenile to mature wood. This paper estimates the age of transition from juvenile to mature wood based on ring specific gravity (SG), proportion of annual ring in latewood, and ring average microfibril angle (MFA). The threshold method and the segmented modeling approach were used to estimate the age of transition. Twenty loblolly pine (Pinus taeda L.) plantations, 20-27 years old, were sampled across five physiographic regions in the southern United States. Increment cores were collected at 1.3 meters from 15 trees in each stand to determine ring specific gravity and proportion of latewood by X-ray densitometry and annual ring MFA by X-ray diffraction. Precisely determining the transition age between juvenile and mature wood was difficult because transition is gradual, not abrupt. The age of transition was found to differ by wood property because these properties mature at different rates due to genetic and environmental factors. Both the threshold and the segmented model approach showed that transition age varied among regions. Both approaches showed that length of juvenility based on ring SG was shorter in the South Atlantic and North Atlantic Coastal Plains (ranging from 5.5 to 7.9 years) compared to that in the Hilly Coastal Plain that ranged from 10.4 to 13.6 years. Using MFA to estimate the age of demarcation, both approaches showed the South Atlantic, Gulf Coastal, and Hilly Coastal Plains had shorter lengths of juvenility (ranging from 8.4 to 10.4 years) than the Piedmont and North Atlantic Coastal Plain (ranging from 10.5 to over 20 years)

    Declines in Religiosity Predict Increases in Violent Crime—but Not Among Countries With Relatively High Average IQ

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    Many scholars have argued that religion reduces violent behavior within human social groups. Here, we tested whether intelligence moderates this relationship. We hypothesized that religion would have greater utility for regulating violent behavior among societies with relatively lower average IQs than among societies with relatively more cognitively gifted citizens. Two studies supported this hypothesis. Study 1, a longitudinal analysis from 1945 to 2010 (with up to 176 countries and 1,046 observations), demonstrated that declines in religiosity were associated with increases in homicide rates—but only in countries with relatively low average IQs. Study 2, a multiverse analysis (171 models) using modern data (97–195 countries) and various controls, consistently confirmed that lower rates of religiosity were more strongly associated with higher homicide rates in countries with lower average IQ. These findings raise questions about how secularization might differentially affect groups of different mean cognitive ability

    AUSSAT battery life test program

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    AUSSAT Pty. Ltd., the Australian National Satellite organization, has contracted with the Hughes Aircraft Company (HAC) for the construction of 3 satellites based on the now familiar HS-376 product line. As part of the AUSSAT contract, HAC is conducting an extensive NiCd battery life test program. The life test program, objectives and test results to date are described. Particular emphasis is given to the evaluation of the FS2117 separator as a future replacement for the Pellon 2505 separator of which only a very limited quantity remains

    Variation in Loblolly Pine Cross-Sectional Microfibril Angle With Tree Height and Physiographic Region

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    The effect of height and physiographic region on whole disk cross-sectional microfibril angle (CSMFA) in loblolly pine (Pinus taeda L.) in the southern United States was evaluated. Whole disk CSMFA was determined at 1.4, 4.6, 7.6, 10.7, and 13.7 m up the stem of 59 trees, representing five physiographic regions. A mixed-effects analysis of variance was performed to test the significance of height, region, and the height by region interaction on CSMFA. Height, region, and the height by region interaction terms were all found to be significant at the 0.10 level. Significant differences were found in CSMFA between 1.4 m and all other height levels in all regions. However, there was no difference between CSMFA at 1.4 m and 13.7 m in the Gulf Coastal Plain. No significant difference was found in CSMFA between 4.5, 7.6, and 10.7 meter-height levels in all regions. CSMFA was found to be significantly larger in the north Atlantic and Piedmont regions compared to the south Atlantic, Gulf, and Hilly regions at all heights. The analysis of variance also indicated that significant variation exists among trees within stands and across stands within regions. This is an indicator that aside from the distinct patterns of CSMFA within trees, other factors including site quality, length of growing season, rainfall, and genetics could possibly play a key role in CSMFA development

    Variation in Loblolly Pine Ring Microfibril Angle in the Southeastern United States

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    The effect of physiographic region on microfibril angle (MFA) in loblolly pine (Pinus taeda L.) in the southern United States was evaluated. MFA was determined at 1.4, 4.6, 7.6, 10.7, and 13.7 m up the stem of 59 trees, representing five physiographic regions. A nonlinear mixed-effects model was developed to test for regional differences in the initial value of MFA, the rate at which MFA changes with ring number from pith, and the lower bound of MFA achieved. Our results suggest that the parameters of interest differ significantly by region. It was found that MFA differs significantly between the South Atlantic, Gulf, and Hilly regions, compared to the North Atlantic and Piedmont regions. The initial value of MFA was found to be smaller in the Piedmont compared to all other regions. Similarly, the rate at which MFA changes with ring number was found to be significantly smaller in the North Atlantic and Piedmont regions. A test of the lower bound of MFA indicates that the Piedmont region has a significantly larger lower asymptote. These results combined indicate that overall, MFA values are larger in the North Atlantic and Piedmont regions

    Contents lists available at ScienceDirect Forest Ecology and Management

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    journal homepage: www.elsevier.com/locate/foreco Effect of early age woody and herbaceous competition control on wood propertie

    Large-Scale Tracing of Ground Water with Sulfur Hexafluoride

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    '20 days protected learning' - students' experiences of an Overseas Nurses Programme - 4 years on: A retrospective survey

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    Background From September 2005 the Nursing and Midwifery Council (NMC) introduced new arrangements for the registration of non-EU overseas nurses which requires all applicants to undertake '20 days of protected learning' time in the UK and for some, a period of supervised practice. A survey was undertaken at Bournemouth University, which offers a '20 days protected learning only' programme, to elicit overseas nurses' demographic details, experiences in completing the programme and their 'final destinations' once registered. Methods An online survey was devised which contained a mixture of tick box and open ended questions which covered demographic details, views on the programme and final destinations This was uploaded to www.SurveyMonkey.com and sent out to nurses who had completed the Overseas Nurses Programme (ONP) with Bournemouth University (n=1050). Quantiative data were analysed using descriptive statistics and the qualitative data were coded and analysed using content analysis . Results There were 251 respondents (27.7% response rate). The typical 'profile' of a nurse who responded to the survey was female, aged 25-40 years and had been qualified for more than 5 years with a bachelors degree. The majority came from Australia on a 2 year working holiday visa and the key final destination in the UK, on registration with the NMC, was working for an agency. There were five key findings regarding experience of the programe. Of those surveyed 61.2% did not feel it necessary to undergo an ONP; 71.6% felt that they should be able to complete the programme on-line in their own country; 64.2% that the ONP should only contain information about delivery of healthcare in UK and Legal and professional (NMC) issues; 57% that European nurses should also undergo the same programme and sit an IELTS test; and 68.2% that the programme was too theory orientated; and should have links to practice (21%). Conclusions The NMC set the admissions criteria for entry to the register and Standards for an ONP. The findings of this survey raise issues regarding the percieved value and use of this approach for overseas nurses, and it may be helpful to take this into account when considering future policy
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