4,604 research outputs found
The Significant Influencing Factors of Xenophobia
This paper serves as a review of the influencing factors of xenophobia and its behavioral products. Two primary categories of influencing factors of xenophobia are discussed: inherent factors and environmental factors. Inherent factors that are considered include genetic factors and personality factors; a variety of perspectives on the impact of these factors are reviewed. Discussion on the impact of environmental factors will focus on the impact of education and inter-group contact on xenophobic attitudes. The factors that influence xenophobia are clearly multifaceted, though conclusions about the extent to which environment and genetics play roles in the development of xenophobia and its by-products (racism, ethnocentrism, etc.) will require more research
Development: Sketch for a Theory of Oct4
SummaryHow is it that Oct4, a transcription factor that controls pluripotency in stem cells, also controls lineage specification? A recent study investigating common Oct4 targets in vertebrate species indicates an evolutionarily conserved role in mediating cell adhesion. This finding may help decipher Oct4’s versatility in governing stem cell behaviors
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Dual gene activation and knockout screen reveals directional dependencies in genetic networks.
Understanding the direction of information flow is essential for characterizing how genetic networks affect phenotypes. However, methods to find genetic interactions largely fail to reveal directional dependencies. We combine two orthogonal Cas9 proteins from Streptococcus pyogenes and Staphylococcus aureus to carry out a dual screen in which one gene is activated while a second gene is deleted in the same cell. We analyze the quantitative effects of activation and knockout to calculate genetic interaction and directionality scores for each gene pair. Based on the results from over 100,000 perturbed gene pairs, we reconstruct a directional dependency network for human K562 leukemia cells and demonstrate how our approach allows the determination of directionality in activating genetic interactions. Our interaction network connects previously uncharacterized genes to well-studied pathways and identifies targets relevant for therapeutic intervention
IS 2009: Changing the Course for Undergraduate IS Model Curricula
In this panel, the joint AIS / ACM Information Systems undergraduate model curriculum task force members together with other curriculum experts will be presenting and discussing the IS 2009 Curriculum Guidelines for Undergraduate Degree Programs in Information Systems document and soliciting IS community feedback regarding ongoing IS curriculum development efforts. As such, the panel discussion will center on the significant components embedded in the newly revised curriculum document. This includes: 1) an introduction to the key principles that guided the development of the document, 2) a list of features incorporated into the new model curricula, 3) the future of curriculum development efforts, and 4) proposed mechanism to solicit feedback from the academy
Do female association preferences predict the likelihood of reproduction?
Sexual selection acting on male traits through female mate choice is commonly inferred from female association preferences in dichotomous mate choice experiments. However, there are surprisingly few empirical demonstrations that such association preferences predict the likelihood of females reproducing with a particular male. This information is essential to confirm association preferences as good predictors of mate choice. We used green swordtails (<i>Xiphophorus helleri</i>) to test whether association preferences predict the likelihood of a female reproducing with a male. Females were tested for a preference for long- or short-sworded males in a standard dichotomous choice experiment and then allowed free access to either their preferred or non-preferred male. If females subsequently failed to produce fry, they were provided a second unfamiliar male with similar sword length to the first male. Females were more likely to reproduce with preferred than non-preferred males, but for those that reproduced, neither the status (preferred/non-preferred) nor the sword length (long/short) of the male had an effect on brood size or relative investment in growth by the female. There was no overall preference based on sword length in this study, but male sword length did affect likelihood of reproduction, with females more likely to reproduce with long- than short-sworded males (independent of preference for such males in earlier choice tests). These results suggest that female association preferences are good indicators of female mate choice but that ornament characteristics of the male are also important
Effect of processing parameters on the morphology development during extrusion of polyethylene tape: an in-line Small-Angle X-ray Scattering (SAXS) study
The in-line development of crystalline morphology and orientation during melt extrusion of low density polyethylene (LDPE) tape at nil and low haul-off speeds has been investigated using Small-Angle X-Ray Scattering (SAXS). The processing parameters, namely haul-off speed and distance down the tape-line have been varied and the resulting crystalline morphology is described from detailed analysis of the SAXS data. Increasing haul-off speed increased orientation in the polymer tape and the resulting morphology could be described in terms of regular lamellar stacking perpendicular to the elongation direction. In contrast, under nil haul-off conditions the tape still showed some orientation down the tape-line, but a shish-kebab structure prevails. The final lamellae thickness (~50 Å) and bulk crystallinity (~20%), were low for all processing conditions investigated, which is attributed to the significant short-chain branching in the polymer acting as point defects limiting lamellae crystal growth
Effect of vessel wettability on the foamability of "ideal" surfactants and "real-world" beer heads
The ability to tailor the foaming properties of a solution by controlling its chemical composition is highly desirable and has been the subject of extensive research driven by a range of applications. However, the control of foams by varying the wettability of the foaming vessel has been less widely reported. This work investigates the effect of the wettability of the side walls of vessels used for the in situ generation of foam by shaking aqueous solutions of three different types of model surfactant systems (non-ionic, anionic and cationic surfactants) along with four different beers (Guinness Original, Banks’s Bitter, Bass No 1 and Harvest Pale). We found that hydrophilic vials increased the foamability only for the three model systems but increased foam stability for all foams except the model cationic system. We then compared stability of beer foams produced by shaking and pouring and demonstrated weak qualitative agreement between both foam methods. We also showed how wettability of the glass controls bubble nucleation for beers and champagne and used this effect to control exactly where bubbles form using simple wettability patterns
Detection of superhumps in XTE J1118+480 approaching quiescence
We present the results of our monitoring of the halo black-hole soft X-ray
transient (SXT) XTE J1118+480 during its decline to quiescence. The system has
decayed 0.5 mags from December 2000 to its present near quiescent level at
R=18.65 (June 2001). The ellipsoidal lightcurve is distorted by an additional
modulation that we interpret as a superhump of P_sh=0.17049(1) d i.e. 0.3%
longer than the orbital period. This implies a disc precession period P_prec=
52 d. After correcting the average phase-folded light curve for veiling, the
amplitude difference between the minima suggests that the binary inclination
angle lies in the range i=71-82 deg. However, we urge caution in the
interpretation of these values because of residual systematic contamination of
the ellipsoidal lightcurve by the complex form of the superhump modulation. The
orbital--mean H-alpha profiles exhibit clear velocity variations with ~500 km/s
amplitude. We interpret this as the first spectroscopic evidence of an
eccentric precessing disc.Comment: Accepted for publication in MNRA
Bacillus anthracis in China and its relationship to worldwide lineages
<p>Abstract</p> <p>Background</p> <p>The global pattern of distribution of 1033 <it>B. anthracis </it>isolates has previously been defined by a set of 12 conserved canonical single nucleotide polymorphisms (canSNP). These studies reinforced the presence of three major lineages and 12 sub-lineages and sub-groups of this anthrax-causing pathogen. Isolates that form the A lineage (unlike the B and C lineages) have become widely dispersed throughout the world and form the basis for the geographical disposition of "modern" anthrax. An archival collection of 191 different <it>B. anthracis </it>isolates from China provides a glimpse into the possible role of Chinese trade and commerce in the spread of certain sub-lineages of this pathogen. Canonical single nucleotide polymorphism (canSNP) and multiple locus VNTR analysis (MLVA) typing has been used to examine this archival collection of isolates.</p> <p>Results</p> <p>The canSNP study indicates that there are 5 different sub-lineages/sub-groups in China out of 12 previously described world-wide canSNP genotypes. Three of these canSNP genotypes were only found in the western-most province of China, Xinjiang. These genotypes were A.Br.008/009, a sub-group that is spread across most of Europe and Asia; A.Br.Aust 94, a sub-lineage that is present in Europe and India, and A.Br.Vollum, a lineage that is also present in Europe. The remaining two canSNP genotypes are spread across the whole of China and belong to sub-group A.Br.001/002 and the A.Br.Ames sub-lineage, two closely related genotypes. MLVA typing adds resolution to the isolates in each canSNP genotype and diversity indices for the A.Br.008/009 and A.Br.001/002 sub-groups suggest that these represent older and established clades in China.</p> <p>Conclusion</p> <p><it>B. anthracis </it>isolates were recovered from three canSNP sub-groups (A.Br.008/009, A.Br.Aust94, and A.Br.Vollum) in the western most portion of the large Chinese province of Xinjiang. The city of Kashi in this province appears to have served as a crossroads for not only trade but the movement of diseases such as anthrax along the ancient "silk road". Phylogenetic inference also suggests that the A.Br.Ames sub-lineage, first identified in the original Ames strain isolated from Jim Hogg County, TX, is descended from the A.Br.001/002 sub-group that has a major presence in most of China. These results suggest a genetic discontinuity between the younger Ames sub-lineage in Texas and the large Western North American sub-lineage spread across central Canada and the Dakotas.</p
Search for Kaluza-Klein Graviton Emission in Collisions at TeV using the Missing Energy Signature
We report on a search for direct Kaluza-Klein graviton production in a data
sample of 84 of \ppb collisions at = 1.8 TeV, recorded
by the Collider Detector at Fermilab. We investigate the final state of large
missing transverse energy and one or two high energy jets. We compare the data
with the predictions from a -dimensional Kaluza-Klein scenario in which
gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for
=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71
TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure
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