A Test of the Standard Hypothesis for the Origin of the HI Holes in Holmberg II

The nearby irregular galaxy Holmberg II has been extensively mapped in HI using the Very Large Array (VLA), revealing intricate structure in its interstellar gas component (Puche et al. 1992). An analysis of these structures shows the neutral gas to contain a number of expanding HI holes. The formation of the HI holes has been attributed to multiple supernova events occurring within wind-blown shells around young, massive star clusters, with as many as 10-200 supernovae required to produce many of the holes. From the sizes and expansion velocities of the holes, Puche et al. assigned ages of ~10^7 to 10^8 years. If the supernova scenario for the formation of the HI holes is correct, it implies the existence of star clusters with a substantial population of late-B, A and F main sequence stars at the centers of the holes. Many of these clusters should be detectable in deep ground-based CCD images of the galaxy. In order to test the supernova hypothesis for the formation of the HI holes, we have obtained and analyzed deep broad-band BVR and narrow-band H-alpha images of Ho II. We compare the optical and HI data and search for evidence of the expected star clusters in and around the HI holes. We also use the HI data to constrain models of the expected remnant stellar population. We show that in several of the holes the observed upper limits for the remnant cluster brightness are strongly inconsistent with the SNe hypothesis described in Puche et al. Moreover, many of the HI holes are located in regions of very low optical surface brightness which show no indication of recent star formation. Here we present our findings and explore possible alternative explanations for the existence of the HI holes in Ho II, including the suggestion that some of the holes were produced by Gamma-ray burst events.Comment: 30 pages, including 6 tables and 3 images. To appear in Astron. Journal (June 1999

Extended HI spiral structure and the figure rotation of triaxial dark halos

The HI disk of the blue compact dwarf (BCD) galaxy NGC 2915 extends to 22 optical scalelengths and shows spiral arms reaching far beyond the optical component. None of the previous theories for spiral structure provide likely explanations for these very extended spiral arms. Our numerical simulations first demonstrate that such large spiral arms can form in an extended gas disk embedded in a massive triaxial dark matter halo with slow figure rotation, through the strong gravitational torque of the rotating halo. We then show that the detailed morphological properties of the developed spirals and rings depend strongly on the pattern speed of the figure rotation, the shape of the triaxial halo, and the inclination of the disk with respect to the plane including the triaxial halo's long and middle axes. These results strongly suggest that the dark matter halo of NGC 2915 is triaxial and has figure rotation. Based on these results, we also suggest that dynamical effects of triaxial halos with figure rotation are important in various aspect of galaxy formation and evolution, such as formation of polar ring galaxies, excitation of non-axisymmetric structures in low surface-brightness galaxies, and gas fueling to the central starburst regions of BCDs.Comment: 13 pages 2 figures (fig.2 = jpg format), accepted by ApJ

Are we overusing IVF?

Peer reviewedPublisher PD

Treatment responsiveness of replicated psychopathy profiles.

Theory and accumulating data suggest systematic heterogeneity among offenders with psychopathic traits. Several empirical investigations converge on the nature of subtypes, but little is known about differences in treatment responsivity. We have used the 4-facet model of the Psychopathy Checklist-Revised (PCL-R) to provide a framework for detecting subtypes. The present study used the full range of PCL-R scores in a sample of male violent offenders (N = 190) to replicate subtypes found in a partly overlapping sample by Neumann, Vitacco, and Mokros (2016), using Latent Profile Analysis (LPA), and subsequently to examine potential differences in treatment responsivity. Four subtypes emerged. Within the prototypical psychopathic group, the distinction between intent-to-treat and completers was crucial. Prototypical psychopathic offenders were significantly more likely to drop out, but completers appeared to proceed through the different phases of treatment in much the same way as the other groups. Clearly, more research is needed to elucidate treatment interfering mechanisms and their associated patient characteristics, particularly for the prototypical psychopathic group. Developing therapeutic strategies to improve treatment compliance is a necessary step in the development of specialized treatment programs for these difficult patients

Clinical Appraisals of Individual Differences in Treatment Responsivity Among Patients With Psychopathy: A Consensual Qualitative Research Study

This study addressed which factors expert clinicians consider crucial in successful completion versus dropout in the mandatory forensic psychiatric treatment of psychopathic patients in the Netherlands. Eleven clinicians were interviewed about patient characteristics, treatment (provider) characteristics, and other factors they deemed associated with failure (transfer to another facility) or completion. The interviews were coded using the guidelines of Consensual Qualitative Research (CQR). Overall, extremely high scores on Psychopathy Checklist–Revised (PCL-R) Facets 1 (Deceitful Interpersonal Style) and 2 (Defective Affective Experience) were thought to impede treatment retention, particularly by its negative impact on motivation and therapeutic relationship. Older patients, those with a prosocial network, and/or patients with comorbid borderline traits appeared to fare better. Treatment success was deemed more likely when treatment goals and expectations are stipulated in a concrete fashion, when an extended and gradual resocialization trajectory is offered, and the treatment team is expert, cohesive, and stable.</p

A flexible data architecture to automate collection of (near) real-time methane sensor data at commercial dairy farms

To reduce methane emissions from the animal production domain, a large intensive research programme has been started in 2018 by the Dutch Ministry of Agriculture, Nature and Food. Part of this programme involves continuous monitoring of methane, by means of sensor measurements, both at the barn and ..

Using MMPI–2–RF Correlates to Elucidate the PCL–R and Its Four Facets in a Sample of Male Forensic Psychiatric Patients

This study documents the associations between the MMPI-2-RF (Ben-Porath & Tellegen, 2008 ) scale scores and the Psychopathy Checklist Revised (PCL-R; Hare, 2003 ) facet scores in a forensic psychiatric sample. Objectives were to determine how the MMPI-2-RF scales might enhance substantive understanding of the nature of the 4 PCL-R facets and to discern possible implications for the treatment of psychopathic patients. A sample of 127 male forensic psychiatric offenders admitted to a Dutch forensic psychiatric hospital completed the PCL-R and the MMPI-2. Exploratory stepwise regression analyses assessed the prediction of the PCL-R total and its facet scores from MMPI-2-RF scales at its 3 hierarchical levels. Conceptually meaningful results emerged at each level of the MMPI-2-RF hierarchy, including several consistent differences between predictor sets across the facets. Interestingly, ideas of persecution (RC6) was a specific predictor of PCL-R Facet 2, a facet noted for its association with treatment failure. Results are compared and contrasted to the extant body of empirical work to date, and some tentative clinical implications are offered

Enabling cooperative behavior for building demand response based on extended joint action learning

This paper explores the use of distributed intelligence to assist the integration of the demand as a flexible resource, to mitigate the emerging uncertainty in the power system, while fulfilling the customer's local needs, i.e., comfort management. More exactly, our contribution is twofold. First, we propose a novel cooperative and decentralized reinforcement learning method, dubbed extended joint action learning (eJAL). Second, we perform a comparison between eJAL to noncooperative decentralized decision making strategies, i.e., Q-learning, and a centralized game theoretic approach, i.e., Nash n-player game. This comparison has been conducted on the basis of grid support effectiveness and the loss of comfort for each customer. Various metrics were used to analyze the advantages and disadvantages of each method. We demonstrated that a range of flexibility requests can be met by providing an optimal energy portfolio of buildings without substantially violating comfort constraints. Moreover, we showed that the proposed eJAL method achieves the highest fairness index.</p

A warped disk model for M33 and the 21-cm line width in spiral galaxies

To determine the actual HI distribution and the velocity field in the outermost disk of the spiral galaxy M33, a tilted-ring model is fitted to 21-cm line data taken with the Arecibo Telescope. Since M33 is one of the main calibrators for the extragalactic distance scale derived through the Tully-Fisher relation, the outer disk warping is of interest for a correct determination and deprojection of the galaxy's line width. Even though our best model predicts small effects on the observed line width of M33, we show that similar outer disk warping in galaxies oriented differently along our line of sight could affect the widths considerably. Therefore there may be systematic effects in the determination of the rotation velocities and dynamic masses of spiral galaxies, whose exact value depends also on which method is used for measuring the galaxy's total line width.Comment: 27 pages, ps files only, ApJ in pres