1,926 research outputs found
Academic buoyancy, student's achievement, and the linking role of control: A cross-lagged analysis of high school students
Background
Previous research has indicated that although academic buoyancy and student's achievement are associated, the relationship is relatively modest.
Aims
We sought to determine whether another construct might link academic buoyancy and student's achievement. Based on prior theoretical and empirical work, we examined a sense of control as one possible linking mechanism.
Sample
The study analysed data from 2,971 students attending 21 Australian high schools.
Methods
We conducted a cross-lagged panel design as a first means of disentangling the relative salience of academic buoyancy, control, and achievement (Phase 1). Based upon these results, we proceeded with follow-up analyses of an ordered process model linking the constructs over time (Phase 2).
Results
Findings showed that buoyancy and achievement were associated with control over time, but not with one another (Phase 1). In addition, control appeared to play a role in how buoyancy influenced achievement and that a cyclical process may operate among the three factors over time (Phase 2).
Conclusion
The findings suggest that control may play an important role in linking past experiences of academic buoyancy and achievement to subsequent academic buoyancy and achievement.The authors would like to thank the Australian Research Council for funding this research
Is our Sun a Singleton?
Most stars are formed in a cluster or association, where the number density
of stars can be high. This means that a large fraction of initially-single
stars will undergo close encounters with other stars and/or exchange into
binaries. We describe how such close encounters and exchange encounters can
affect the properties of a planetary system around a single star. We define a
singleton as a single star which has never suffered close encounters with other
stars or spent time within a binary system. It may be that planetary systems
similar to our own solar system can only survive around singletons. Close
encounters or the presence of a stellar companion will perturb the planetary
system, often leaving planets on tighter and more eccentric orbits. Thus
planetary systems which initially resembled our own solar system may later more
closely resemble some of the observed exoplanet systems.Comment: 2 pages, 1 figure. To be published in the proceedings of IAUS246
"Dynamical Evolution of Dense Stellar Systems". Editors: E. Vesperini (Chief
Editor), M. Giersz, A. Sill
Ideal cardiovascular health and psychosocial risk factors among Finnish female municipal workers
Aims: Ideal cardiovascular health has been defined by the American Heart Association as the absence of disease and the presence of seven key health factors and behaviours. However, little is known about the mental aspects associated with ideal cardiovascular health metrics. The objective of this study was to assess the relationships between psychosocial risk factors and ideal cardiovascular health metrics among Finnish women at municipal work units. Method: A cross-sectional study was conducted in Finland among 732 female employees (mean +/- SD age 48 +/- 10 years) from ten work units in 2014. Ideal cardiovascular health metrics were evaluated with a physical examination, laboratory tests, medical history and self-administrated questionnaires. Psychosocial risk factors (social isolation, stress, depressive symptoms, anxiety, hostility and type D personality) were assessed with core questions as suggested by the European Society of Cardiology. Results: The prevalence of having 5-7 ideal cardiovascular health metrics was 183 (25.0%), of whom 54.1% had at least one psychosocial risk factor. Anxiety (31.3%), work stress (30.7%) and type D personality (26.1%) were the most prevalent of the psychosocial risk factors. The prevalence of depressive symptoms (pPeer reviewe
A Method to Polarize Stored Antiprotons to a High Degree
Polarized antiprotons can be produced in a storage ring by spin--dependent
interaction in a purely electron--polarized hydrogen gas target. The polarizing
process is based on spin transfer from the polarized electrons of the target
atoms to the orbiting antiprotons. After spin filtering for about two beam
lifetimes at energies MeV using a dedicated large acceptance
ring, the antiproton beam polarization would reach . Polarized
antiprotons would open new and unique research opportunities for spin--physics
experiments in interactions
Single nucleotide polymorphisms in Plasmodium falciparum V type H+ pyrophosphatase gene (pfvp2) and their associations with pfcrt and pfmdr1 polymorphisms
"Uncorrected proof"BACKGROUND:
Chloroquine resistance in Plasmodium falciparum malaria has been associated with pfcrt 76T (chloroquine resistance transporter gene) and pfmdr1 86Y (multidrug resistance gene 1) alleles. Pfcrt 76T enables transport of protonated chloroquine out of the parasites digestive vacuole resulting in a loss of hydrogen ions (H(+)). V type H(+) pyrophosphatase (PfVP2) is thought to pump H(+) into the digestive vacuole. This study aimed to describe the geographic distribution of single nucleotide polymorphisms in pfvp2 and their possible associations with pfcrt and pfmdr1 polymorphisms.
METHODS:
Blood samples from 384 patients collected (1981-2009) in Honduras (n=35), Colombia (n=50), Liberia (n=50), Guinea Bissau (n=50), Tanzania (n=50), Iran (n=50), Thailand (n=49) and Vanuatu (n=50) were analysed. The pfcrt 72-76 haplotype, pfmdr1 copy numbers, pfmdr1 N86Y and pfvp2 V405I, K582R and P711S alleles were identified using PCR based methods.
RESULTS:
Pfvp2 was amplified in 344 samples. The pfvp2 allele proportions were V405 (97%), 405I (3%), K582 (99%), 582R (1%), P711 (97%) and 711S (3%). The number of patients with any of pfvp2 405I, 582R and/or 711S were as follows: Honduras (2/30), Colombia (0/46), Liberia (7/48), Guinea-Bissau (4/50), Tanzania (3/48), Iran (3/50), Thailand (1/49) and Vanuatu (0/31). The alleles were most common in Liberia (P=0.01) and Liberia+Guinea-Bissau (P=0.01). The VKP haplotype was found in 189/194 (97%) and 131/145 (90%) samples harbouring pfcrt 76T and pfcrt K76 respectively (P=0.007).
CONCLUSIONS:
The VKP haplotype was dominant. Most pfvp2 405I, 582R and 711S SNPs were seen where CQ resistance was not highly prevalent at the time of blood sampling possibly due to greater genetic variation prior to the bottle neck event of spreading CQ resistance. The association between the pfvp2 VKP haplotype and pfcrt 76T, which may indicate that pfvp2 is involved in CQ resistance, should therefore be interpreted with caution.This work was supported by Swedish International Development Cooperation Agency, Department for research Cooperation (Sida-SAREC Contribution no 75007082/03) and Sigurd och Elsa Goljes Minne Fund (project No. LA2010-0537). MIV is recipient of Post Doctoral fellowship from Fundacao para a Ciencia e Tecnologia (FCT)/Ministerio da Ciencia e Ensino Superior, Portugal - MCES (ref. SFRH/BPD/76614/2011). JU has a postdoctoral position funded by Stockholms lans landsting
Planetary Dynamics and Habitable Planet Formation In Binary Star Systems
Whether binaries can harbor potentially habitable planets depends on several
factors including the physical properties and the orbital characteristics of
the binary system. While the former determines the location of the habitable
zone (HZ), the latter affects the dynamics of the material from which
terrestrial planets are formed (i.e., planetesimals and planetary embryos), and
drives the final architecture of the planets assembly. In order for a habitable
planet to form in a binary star system, these two factors have to work in
harmony. That is, the orbital dynamics of the two stars and their interactions
with the planet-forming material have to allow terrestrial planet formation in
the habitable zone, and ensure that the orbit of a potentially habitable planet
will be stable for long times. We have organized this chapter with the same
order in mind. We begin by presenting a general discussion on the motion of
planets in binary stars and their stability. We then discuss the stability of
terrestrial planets, and the formation of potentially habitable planets in a
binary-planetary system.Comment: 56 pages, 29 figures, chapter to appear in the book: Planets in
Binary Star Systems (Ed. N. Haghighipour, Springer publishing company
Long-time discrete particle effects versus kinetic theory in the self-consistent single-wave model
The influence of the finite number N of particles coupled to a monochromatic
wave in a collisionless plasma is investigated. For growth as well as damping
of the wave, discrete particle numerical simulations show an N-dependent long
time behavior resulting from the dynamics of individual particles. This
behavior differs from the one due to the numerical errors incurred by Vlasov
approaches. Trapping oscillations are crucial to long time dynamics, as the
wave oscillations are controlled by the particle distribution inhomogeneities
and the pulsating separatrix crossings drive the relaxation towards thermal
equilibrium.Comment: 11 pages incl. 13 figs. Phys. Rev. E, in pres
Universal Rights and Wrongs
This paper argues for the important role of customers as a source of competitive advantage and firm growth, an issue which has been largely neglected in the resource-based view of the firm. It conceptualizes Penrose’s (1959) notion of an ‘inside track’ and illustrates how in-depth knowledge about established customers combines with joint problem-solving activities and the rapid assimilation of new and previously unexploited skills and resources. It is suggested that the inside track represents a distinct and perhaps underestimated way of generating rents and securing long-term growth. This also implies that the sources of sustainable competitive advantage in important respects can be sought in idiosyncratic interfirm relationships rather than within the firm itself
Testing the theory of immune selection in cancers that break the rules of transplantation
Modification of cancer cells likely to reduce their immunogenicity, including loss or down-regulation of MHC molecules, is now well documented and has become the main support for the concept of immune surveillance. The evidence that these modifications, in fact, result from selection by the immune system is less clear, since the possibility that they may result from reorganized metabolism associated with proliferation or from cell de-differentiation remains. Here, we (a) survey old and new transplantation experiments that test the possibility of selection and (b) survey how transmissible tumours of dogs and Tasmanian devils provide naturally evolved tests of immune surveillance
A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
The guanidine functional group, displayed most prominently in the amino acid arginine, one of the fundamental building blocks of life, is an important structural element found in many complex natural products and pharmaceuticals. Owing to the continual discovery of new guanidinecontaining natural products and designed small molecules, rapid and efficient guanidinylation methods are of keen interest to synthetic and medicinal organic chemists. Because the nucleophilicity and basicity of guanidines can affect subsequent chemical transformations, traditional, indirect guanidinylation is typically pursued. Indirect methods commonly employ multiple protection steps involving a latent amine precursor, such as an azide, phthalimide, or carbamate. By circumventing these circuitous methods and employing a direct guanidinylation reaction early in the synthetic sequence, it was possible to forge the linear terminal guanidine containing backbone of clavatadine A to realize a short and streamlined synthesis of this potent factor XIa inhibitor. In practice, guanidine hydrochloride is elaborated with a carefully constructed protecting array that is optimized to survive the synthetic steps to come. In the preparation of clavatadine A, direct guanidinylation of a commercially available diamine eliminated two unnecessary steps from its synthesis. Coupled with the wide variety of known guanidine protecting groups, direct guanidinylation evinces a succinct and efficient practicality inherent to methods that find a home in a synthetic chemist\u27s toolbox
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