The Light Curve and Internal Magnetic Field of the Mode-Switching Pulsar PSR B0943+10

A number of radio pulsars exhibit intriguing mode-switching behavior. Recent observations of PSR B0943+10 revealed correlated radio and X-ray mode switches, providing a new avenue for understanding this class of objects. The large X-ray pulse fraction observed during the radio quiet phase (Q mode) was previously interpreted as a result of changing obscuration of X-rays by dense magnetosphere plasma. We show that the large X-ray pulse fraction can be explained by including the beaming effect of a magnetic atmosphere, while remaining consistent with the dipole field geometry constrained by radio observations. We also explore a more extreme magnetic field configuration, where a magnetic dipole displaced from the center of the star produces two magnetic polar caps of different sizes and magnetic field strengths. These models are currently consistent with data in radio and X-rays and can be tested or constrained by future X-ray observations.Comment: 5 pages, 5 figures, submitted to ApJ

The sex offender in Oregon : fact and fallacy

The principal objective of this study was to examine the proposition, advanced by several authorities, that the views, attitudes and beliefs of the public concerning the sex offender and his offense are characterized by fallacy, stereotype and misconception. That the approach to the problem of the sex offense has been and continues to be primarily legislative is a fact that can be demonstrated; and that legislation reflects and is influenced by public attitudes and beliefs is a premise that can be supported. Hence the accuracy or inaccuracy of these public attitudes and beliefs will have a bearing on the legislation enacted. Yet no systematic study could be discovered by the researchers either validating or invalidating the proposition as stated. It was to this end that the project was undertaken. The method of approach was to establish some factual baseline data about sex offenders and to examine the assumptions of the public about this data. Difficulties in defining both populations, the sex offenders and the public, were met by limiting the former to those individuals admitted to the sex offender program at Oregon State Hospital under any of the provisions of Oregon\u27s Sexually Dangerous” law, ORS 42.6, and the latter to the first-year graduate social work students at Portland State University. The problem of distinguishing fact from fallacy was handled by limiting the data to recorded and verifiable information drawn from case records. These necessary limitations resulted in the reduction of the above-described proposition to the much narrow hypothesis that beginning social work students at Portland State University will make inaccurate assumptions about the characteristics of the sex offender population at Oregon State Hospital. Although this reduction resulted in some loss of primary value, other secondary gains realized from the study as designed include the compilation of data on a population not heretofore studied and the communication of knowledge and stimulation of interest in areas where knowledge is lacking. This latter factor is of particular importance when the nature of the respondent population is taken into account--they are not only members of the legislation-influencing public, they are future professionals who will be in a position to bring other approaches to bear on the problem of the sex offender and his offense. Procedure consisted of the gathering and tabulation of factual data from the case records of 79 offenders and the use of this information as the basis for construction of a questionnaire-type instrument for assessing the accuracy of the assumptions of the respondents concerning the characteristics of the offender, his offense and his victim(s). The instrument also included 12 statements of attitude claimed to be common misconceptions held by the lay public concerning sex offenders. The most significant finding of the study was that the exploratory hypothesis was not supported. The respondents made fewer inaccurate than accurate assumptions about the sex offender population at Oregon State Hospital. Moreover, they disagreed with 10 out of the 12 attitudinal statements. It is not concluded on the basis of this finding, however, that the initial proposition is therefore invalidated. The atypical character of both populations and the gross nature of the methodology employed preclude such a verdict. On the other hand, it is felt that the secondary benefits have been realized; and that, furthermore, the study represents a meaningful addition to the store of knowledge both about the sex offender and his offense and about public attitudes toward them

Riboswitch identification using Ligase-Assisted Selection for the Enrichment of Responsive Ribozymes (LigASERR)

In vitro selection of ligand-responsive ribozymes can identify rare, functional sequences from large libraries. While powerful, key caveats of this approach include lengthy and demanding experimental workflows; unpredictable experimental outcomes and unknown functionality of enriched sequences in vivo. To address the first of these limitations we developed Ligase-Assisted Selection for the Enrichment of Responsive Ribozymes (LigASERR). LigASERR is scalable, amenable to automation and requires less time to implement compared to alternative methods. To improve the predictability of experiments, we modelled the underlying selection process, predicting experimental outcomes based on sequence and population parameters. We applied this new methodology and model to the enrichment of a known, in vitro-selected sequence from a bespoke library. Prior to implementing selection, conditions were optimised and target sequence dynamics accurately predicted for the majority of the experiment. In addition to enriching the target sequence, we identified two new, theophylline-activated ribozymes. Notably, all three sequences yielded riboswitches functional in Escherichia coli, suggesting LigASERR and similar in vitro selection methods can be utilised for generating functional riboswitches in this organism

Renormalization group theory for finite-size scaling in extreme statistics

We present a renormalization group (RG) approach to explain universal features of extreme statistics, applied here to independent, identically distributed variables. The outlines of the theory have been described in a previous Letter, the main result being that finite-size shape corrections to the limit distribution can be obtained from a linearization of the RG transformation near a fixed point, leading to the computation of stable perturbations as eigenfunctions. Here we show details of the RG theory which exhibit remarkable similarities to the RG known in statistical physics. Besides the fixed points explaining universality, and the least stable eigendirections accounting for convergence rates and shape corrections, the similarities include marginally stable perturbations which turn out to be generic for the Fisher-Tippett-Gumbel class. Distribution functions containing unstable perturbations are also considered. We find that, after a transitory divergence, they return to the universal fixed line at the same or at a different point depending on the type of perturbation.Comment: 15 pages, 8 figures, to appear in Phys. Rev.

Application of the direct Liapunov method to the problem of symmetric stability in the atmosphere

The problem of symmetric stability is examined within the context of the direct Liapunov method. The sufficient conditions for stability derived by Fjørtoft are shown to imply finite-amplitude, normed stability. This finite-amplitude stability theorem is then used to obtain rigorous upper bounds on the saturation amplitude of disturbances to symmetrically unstable flows.By employing a virial functional, the necessary conditions for instability implied by the stability theorem are shown to be in fact sufficient for instability. The results of Ooyama are improved upon insofar as a tight two-sided (upper and lower) estimate is obtained of the growth rate of (modal or nonmodal) symmetric instabilities.The case of moist adiabatic systems is also considered

The effect of a regional increase in ocean surface roughness on the tropospheric circulation: a GCM experiment

The sensitivity of the atmospheric circulation to an increase in ocean surface roughness in the Southern Hemisphere storm track is investigated in a paired general circulation model experiment. Such a change in sea roughness could be induced by ocean waves generated by storms. Two extended permanent-July runs are made. One with standard sea surface roughness, the other with ten times as a large surface roughness over open sea poleward of 40-degrees-S. The regional increase in ocean surface roughness significantly modifies the tropospheric circulation in the Southern Hemisphere. The strongest effect is the reduction of tropospheric winds (by 2 m/s or 100%) above the area with increased roughness. The poleward eddy momentum flux is reduced in the upper troposphere and the meridional eddy sensible heat flux is reduced in the lower troposphere. Zonal mean and eddy kinetic energy are consistently reduced

Efeito de diferentes tecnologias de armazenamento na qualidade de maçãs.

O objetivo desse estudo foi avaliar as mudanças físico-químicas, sensoriais e moleculares associadas às condições de armazenamento e a relação dessas características com a perda de qualidade em maçãs

The backbone of the climate network

We propose a method to reconstruct and analyze a complex network from data generated by a spatio-temporal dynamical system, relying on the nonlinear mutual information of time series analysis and betweenness centrality of complex network theory. We show, that this approach reveals a rich internal structure in complex climate networks constructed from reanalysis and model surface air temperature data. Our novel method uncovers peculiar wave-like structures of high energy flow, that we relate to global surface ocean currents. This points to a major role of the oceanic surface circulation in coupling and stabilizing the global temperature field in the long term mean (140 years for the model run and 60 years for reanalysis data). We find that these results cannot be obtained using classical linear methods of multivariate data analysis, and have ensured their robustness by intensive significance testing.Comment: 6 pages, 5 figure