5,729 research outputs found

    Multi-Stem Mechanized Harvesting Operation Analysis – Application of Arena 9 Discrete-event Simulation Software in Zululand, South Africa

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    Time studies were carried out on a stump-to-mill multi-stem Eucalyptus harvesting and transport operation in Zululand, South Africa in 2007. A simulation model (System 1) of this system was subsequently built using a commercial simulation software package (Arena 9) and data from the time studies incorporated into the model. Following this, two hypothetical stump-to-mill multi-stem models (Systems 2 and 3) were built using Arena 9 and parameterized input data. All models were found to adequately represent reality. Simulated harvesting system balance was improved through normalization of machine utilization in Systems 2 and 3. Production improvements were predicted with simulated timber production per month increasing by 31.1% and 30.8%, from System 1 with three trucks, to System 2 with four trucks, and System 3 with four trucks, respectively. Cost reduction was predicted, with the cost per unit of timber decreasing by 12.5% and 4.1%, from System 1 with three trucks, to System 2 with four trucks and System 3 with four trucks, respectively. Beneficial operational techniques were also confirmed using the simulation models. In the studied conditions delimbing and debarking of full trees into tree lengths at roadside with delimber-debarkers before cross-cutting and loading with a slasher was predicted to be $0.65/m3 cheaper than delimbing, de-barking, and cross-cutting full trees into pulpwood with processors at the landing and then loading with a loader. Usability of Arena 9 in modeling forest harvesting operations was concluded as acceptable, but required detailed background logic inclusion

    Optimization of DNA extraction from human urinary samples for mycobiome community profiling.

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    IntroductionRecent data suggest the urinary tract hosts a microbial community of varying composition, even in the absence of infection. Culture-independent methodologies, such as next-generation sequencing of conserved ribosomal DNA sequences, provide an expansive look at these communities, identifying both common commensals and fastidious organisms. A fundamental challenge has been the isolation of DNA representative of the entire resident microbial community, including fungi.Materials and methodsWe evaluated multiple modifications of commonly-used DNA extraction procedures using standardized male and female urine samples, comparing resulting overall, fungal and bacterial DNA yields by quantitative PCR. After identifying protocol modifications that increased DNA yields (lyticase/lysozyme digestion, bead beating, boil/freeze cycles, proteinase K treatment, and carrier DNA use), all modifications were combined for systematic confirmation of optimal protocol conditions. This optimized protocol was tested against commercially available methodologies to compare overall and microbial DNA yields, community representation and diversity by next-generation sequencing (NGS).ResultsOverall and fungal-specific DNA yields from standardized urine samples demonstrated that microbial abundances differed significantly among the eight methods used. Methodologies that included multiple disruption steps, including enzymatic, mechanical, and thermal disruption and proteinase digestion, particularly in combination with small volume processing and pooling steps, provided more comprehensive representation of the range of bacterial and fungal species. Concentration of larger volume urine specimens at low speed centrifugation proved highly effective, increasing resulting DNA levels and providing greater microbial representation and diversity.ConclusionsAlterations in the methodology of urine storage, preparation, and DNA processing improve microbial community profiling using culture-independent sequencing methods. Our optimized protocol for DNA extraction from urine samples provided improved fungal community representation. Use of this technique resulted in equivalent representation of the bacterial populations as well, making this a useful technique for the concurrent evaluation of bacterial and fungal populations by NGS

    Scaling the heights of positive psychology: A systematic review of measurement scales

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    The volume of empirical research on positive psychology topics has grown substantially over the past two decades.  This review examines how constructs in positive psychology have been operationalized, measured, validated, cited, and applied to build the science. Based on an archive of 972 empirical articles linked to positive psychology, this review found that 762 articles used at least one measurement scale; 312 measures were created or adapted.  Findings reveal a wide range of scales being used to measure a variety of constructs, including scales on both life-enhancing and life-depleting constructs.  Key characteristics such as journals, constructs, and scale development and validation information are discussed.  There are some reliability analyses and validations occurring within the field, but the creation of new measures far outpaces the validation of existing measures.  Weaknesses such as multiple operationalizations may be rooted in inadequate discourse and synthesis.  We call for further cross-pollination for a more scientifically robust scholarship in positive psychology

    Unique transcriptomic landscapes identified in idiopathic spontaneous and infection related preterm births compared to normal term births.

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    Preterm birth (PTB) is leading contributor to infant death in the United States and globally, yet the underlying mechanistic causes are not well understood. Histopathological studies of preterm birth suggest advanced villous maturity may have a role in idiopathic spontaneous preterm birth (isPTB). To better understand pathological and molecular basis of isPTB, we compared placental villous transcriptomes from carefully phenotyped cohorts of PTB due to infection or isPTB between 28-36 weeks gestation and healthy term placentas. Transcriptomic analyses revealed a unique expression signature for isPTB distinct from the age-matched controls that were delivered prematurely due to infection. This signature included the upregulation of three IGF binding proteins (IGFBP1, IGFBP2, and IGFBP6), supporting a role for aberrant IGF signaling in isPTB. However, within the isPTB expression signature, we detected secondary signature of inflammatory markers including TNC, C3, CFH, and C1R, which have been associated with placental maturity. In contrast, the expression signature of the gestational age-matched infected samples included upregulation of proliferative genes along with cell cycling and mitosis pathways. Together, these data suggest an isPTB molecular signature of placental hypermaturity, likely contributing to the premature activation of inflammatory pathways associated with birth and providing a molecular basis for idiopathic spontaneous birth

    THE CHOICE OF A SURVIVING SIBLING AS “SCAPEGOAT” IN SOME CASES OF MATERNAL BEREAVEMENT—A CASE REPORT

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    — This paper presents a description of a pathological variation of the mourning process in mothers who have suffered a narcissistically damaging psychological or actual loss of a child. A surviving sibling chosen as a displacement object for the mother's sense of guilt and self-hatred. The parent-child estrangement continues for years after the trauma with an extremity and severity that often necessitates court intervention. A case illustration is presented and a concluding suggestion that counseling by available professionals at the time of the bereavement would be both economical and effective in forestalling this variety of pathological family scapegoating.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73748/1/j.1469-7610.1975.tb00367.x.pd

    Biophysical and Functional Characterization of Rhesus Macaque IgG Subclasses

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    Antibodies raised in Indian rhesus macaques [Macaca mulatta (MM)] in many preclinical vaccine studies are often evaluated in vitro for titer, antigen-recognition breadth, neutralization potency, and/or effector function, and in vivo for potential associations with protection. However, despite reliance on this key animal model in translation of promising candidate vaccines for evaluation in first in man studies, little is known about the properties of MM immunoglobulin G (IgG) subclasses and how they may compare to human IgG subclasses. Here, we evaluate the binding of MM IgG1, IgG2, IgG3, and IgG4 to human Fc gamma receptors (FcgammaR) and their ability to elicit the effector functions of human FcgammaR-bearing cells, and unlike in humans, find a notable absence of subclasses with dramatically silent Fc regions. Biophysical, in vitro, and in vivo characterization revealed MM IgG1 exhibited the greatest effector function activity followed by IgG2 and then IgG3/4. These findings in rhesus are in contrast with the canonical understanding that IgG1 and IgG3 dominate effector function in humans, indicating that subclass-switching profiles observed in rhesus studies may not strictly recapitulate those observed in human vaccine studies

    Novel Characteristics of Valveless Pumping

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    This study investigates the occurrence of valveless pumping in a fluidfilled system consisting of two open tanks connected by an elastic tube. We show that directional flow can be achieved by introducing a periodic pinching applied at an asymmetrical location along the tube, and that the flow direction depends on the pumping frequency. We propose a relation between wave propagation velocity, tube length, and resonance frequencies associated with shifts in the pumping direction using numerical simulations. The eigenfrequencies of the system are estimated from the linearized system, and we show that these eigenfrequencies constitute the resonance frequencies and the horizontal slope frequencies of the system; 'horizontal slope frequency' being a new concept. A simple model is suggested, explaining the effect of the gravity driven part of the oscillation observed in response to the tank and tube diameter changes. Results are partly compared with experimental findings.Art. no. 22450

    Bounded-Angle Spanning Tree: Modeling Networks with Angular Constraints

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    We introduce a new structure for a set of points in the plane and an angle α\alpha, which is similar in flavor to a bounded-degree MST. We name this structure α\alpha-MST. Let PP be a set of points in the plane and let 0<α2π0 < \alpha \le 2\pi be an angle. An α\alpha-ST of PP is a spanning tree of the complete Euclidean graph induced by PP, with the additional property that for each point pPp \in P, the smallest angle around pp containing all the edges adjacent to pp is at most α\alpha. An α\alpha-MST of PP is then an α\alpha-ST of PP of minimum weight. For α<π/3\alpha < \pi/3, an α\alpha-ST does not always exist, and, for απ/3\alpha \ge \pi/3, it always exists. In this paper, we study the problem of computing an α\alpha-MST for several common values of α\alpha. Motivated by wireless networks, we formulate the problem in terms of directional antennas. With each point pPp \in P, we associate a wedge WpW_p of angle α\alpha and apex pp. The goal is to assign an orientation and a radius rpr_p to each wedge WpW_p, such that the resulting graph is connected and its MST is an α\alpha-MST. (We draw an edge between pp and qq if pWqp \in W_q, qWpq \in W_p, and pqrp,rq|pq| \le r_p, r_q.) Unsurprisingly, the problem of computing an α\alpha-MST is NP-hard, at least for α=π\alpha=\pi and α=2π/3\alpha=2\pi/3. We present constant-factor approximation algorithms for α=π/2,2π/3,π\alpha = \pi/2, 2\pi/3, \pi. One of our major results is a surprising theorem for α=2π/3\alpha = 2\pi/3, which, besides being interesting from a geometric point of view, has important applications. For example, the theorem guarantees that given any set PP of 3n3n points in the plane and any partitioning of the points into nn triplets, one can orient the wedges of each triplet {\em independently}, such that the graph induced by PP is connected. We apply the theorem to the {\em antenna conversion} problem
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