CC201 Soybean Weed Control

CC201 discusses soybean weed control including methods and types of weed control

CC201 Soybean Weed Control

CC201 discusses soybean weed control including methods and types of weed control

Electrovac pppp-waves

New exact solutions of the Einstein-Maxwell field equations that describe $pp$-waves are presented

Swearing as a response to pain: A cross-cultural comparison of British and Japanese participants

Background and aims: Research suggests swearing can moderate pain perception. The present study assessed whether changes in pain perception due to swearing reflect a "scripting" effect by comparing swearing as a response to pain in native English and Japanese speakers. Cognitive psychology denotes a 'script' to be a sequence of learnt behaviours expected for given situations. Japanese participants were included as they rarely, if ever, swear as a response to pain and therefore do not possess an available script for swearing in the context of pain. It was hypothesised that Japanese participants would demonstrate less tolerance and more sensitivity to pain than English participants, and - due to a lack of an available script of swearing in response to pain - that Japanese participants would not experience swearword mediated hypoalgesia. Methods: Fifty-six native English (mean age = 23 years) and 39 Japanese (mean age = 21) speakers completed a cold-pressor task whilst repeating either a swear on control word. A 2 (culture; Japanese, British). ×. 2 (word; swear; non-swear) design explored whether Japanese participants showed the same increase in pain tolerance and experienced similar levels of perceived pain when a swearing intervention was used as British participants. Pain tolerance was assessed by the number of seconds participants could endure of cold-pressor exposure and self-report pain measurements. Levels of perceived pain were assessed using a 120-mm horizontal visual analogue scale anchored by descriptors in the participant's native language of "no pain" (left) and "terrible pain" (right). The participant was asked to mark a 10. mm vertical line to indicate overall pain intensity. The score was measured from the zero anchor to the participant's mark. Results: Japanese participants reported higher levels of pain (p <. 0.005) and displayed lower pain tolerance than British participants (p <. 0.05). Pain tolerance increased in swearers regardless of cultural background (p <. 0.001) and no interaction was found between word group and culture (p = 0.96), thereby suggesting that swearing had no differential effect related to the cultural group of the participant. Conclusions: The results replicate previous findings that swearing increases pain tolerance and that individuals from an Asian ethnic background experience greater levels of perceived pain than those from a Caucasian ethnic background. However, these results do not support the idea of pain perception modification due to a "scripting" effect. This is evidenced as swearword mediated hypoalgesia occurs irrespective of participant cultural background. Rather, it is suggested that modulation of pain perception may occur through activation of descending inhibitory neural pain mechanisms. Implications: As swearing can increase pain tolerance in both Japanese and British people, it may be suggested that swearword mediated hypoalgesia is a universal phenomenon that transcends socio-cultural learnt behaviours. Furthermore, swearing could be encouraged as an intervention to help people cope with acute painful stimuli

Dipole anisotropies of IRAS galaxies and the contribution of a large-scale local void

Recent observations of dipole anisotropies show that the velocity of the Local Group (\Vec v_{\rm G}) induced by the clustering of IRAS galax ies has an amplitude and direction similar to those of the velocity of Cosmic Microwave Background dipole anisotropy (\Vec v_{\rm CMB}), but the difference | \Vec v_{\rm G} - \Vec v_{\rm CMB} | is still $\sim 170$ km/s, which is about 28% of |\Vec v_{\rm CMB} |. Here we consider the possibility that the origin of this difference comes from a hypothetical large-scale local void, with which we can account for the accelerating behavior of type Ia supernovae due to the spatial inhomogeneity of the Hubble constant without dark energies and derive the constraint to the model parameters of the local void. It is found as a result that the distance between the Local Group and the center of the void must be $(10 -- 20) h^{-1}$ Mpc, whose accurate value depends on the background model parameters.Comment: 13 pages, 1 figure, to be published in ApJ 584, No.2 (2003

Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I

We have embarked on a project, under the aegis of the Nearby Stars (NStars)/ Space Interferometry Mission Preparatory Science Program to obtain spectra, spectral types, and, where feasible, basic physical parameters for the 3600 dwarf and giant stars earlier than M0 within 40 parsecs of the sun. In this paper we report on the results of this project for the first 664 stars in the northern hemisphere. These results include precise, homogeneous spectral types, basic physical parameters (including the effective temperature, surface gravity and the overall metallicity, [M/H]) and measures of the chromospheric activity of our program stars. Observed and derived data presented in this paper are also available on the project's website at http://stellar.phys.appstate.edu/

The Dipole Anisotropy of the First All-Sky X-ray Cluster Sample

We combine the recently published CIZA galaxy cluster catalogue with the XBACs cluster sample to produce the first all-sky catalogue of X-ray clusters in order to examine the origins of the Local Group's peculiar velocity without the use of reconstruction methods to fill the traditional Zone of Avoidance. The advantages of this approach are (i) X-ray emitting clusters tend to trace the deepest potential wells and therefore have the greatest effect on the dynamics of the Local Group and (ii) our all-sky sample provides data for nearly a quarter of the sky that is largely incomplete in optical cluster catalogues. We find that the direction of the Local Group's peculiar velocity is well aligned with the CMB as early as the Great Attractor region 40 h^-1 Mpc away, but that the amplitude of its dipole motion is largely set between 140 and 160 h^-1 Mpc. Unlike previous studies using galaxy samples, we find that without Virgo included, roughly ~70% of our dipole signal comes from mass concentrations at large distances (>60 h^-1 Mpc) and does not flatten, indicating isotropy in the cluster distribution, until at least 160 h^-1 Mpc. We also present a detailed discussion of our dipole profile, linking observed features to the structures and superclusters that produce them. We find that most of the dipole signal can be attributed to the Shapley supercluster centered at about 150 h^-1 Mpc and a handful of very massive individual clusters, some of which are newly discovered and lie well in the Zone of Avoidance.Comment: 15 Pages, 9 Figures. Accepted by Ap

Perturbations with angular momentum of Robinson-Trautman spacetimes

We study the possible asymptotically flat perturbations of Robinson-Trautman spacetimes. We differentiate between algebraically special perturbations and general perturbations. The equations that determine physically realistic spacetimes with angular momentum are presented.Comment: 23 pages, no figure

A classification of spherically symmetric spacetimes

A complete classification of locally spherically symmetric four-dimensional Lorentzian spacetimes is given in terms of their local conformal symmetries. The general solution is given in terms of canonical metric types and the associated conformal Lie algebras. The analysis is based upon the local conformal decomposition into 2+2 reducible spacetimes and the Petrov type. A variety of physically meaningful example spacetimes are discussed