Galaxy clustering and dynamics from redshift surveys

The clustering and dynamical properties of the 368 galaxies in the redshift surveys of Metcalfe et al. (1989) and Parker et al. (1986) are investigated. These galaxies were selected from ten high galactic latitude fields complete to a magnitude limit of m(b(_J))<17(^m). These complement the five similarly selected fields in the survey of Peterson et al. (1986) and so the overall clustering and dynamical properties of all three samples are discussed. Initial studies of the distribution of galaxies in the survey of Peterson et al. were carried out by Bean (1983). This thesis extends that earlier work by examining the conclusions of Bean in the larger volume of the new surveys considered here. It is found that, whilst the combined estimate of the line-of-sight peculiar motions in the three samples together is in reasonable accord with that found previously, the range of peculiar motions in the individual samples is larger than previously anticipated. The rms pair-wise velocity (w(^2))(^1/2) is found to be (w(^2)(^1/2)=(600±140)kms(^-1) in the Metcalfe et al. survey as compared to (w(^2))(^1/2)=(0±240)kms(^-1) and w(w(^2))(^1/2)=(190± 90)(^-1) in the Parker et al. and Peterson et al. samples, respectively. These estimates of the motions of galaxies at spatial scales of ~1h(^-1) Mpc (H(_o)=100kms(^-1) Mpc(^-1)) together with measures of the clustering provide constraints on the mean mass density of the Universe through the Cosmic Virial Theorem. It is found that the mean mass density parameter for the three samples considered as a whole is Ω(_o)=0.18±0.09, on the assumption that galaxies trace the mass distribution, and this constraint is similar to that obtained previously mainly because of the larger range of peculiar motions found. The clustering distribution of the galaxies in the new samples was investigated on spatial scales ranging from a few up to -l00h(^-1) Mpc. It was found from the number-redshift and number-magnitude counts that these samples were fairly homogeneous at the largest scales and in good agreement with previous results from the Peterson et al. catalogue. Thus using these samples to estimate the mean clustering properties of galaxies, it was found, from the two-point correlation function ~5(s), that the galaxies in the new samples appear to exhibit a preferred clustering length at -2h(^-1) Mpc and this confirms the 'shoulder ' detected in the correlation function of the Peterson et al. data by Bean (1983). On the basis that this shoulder is a real spatial feature (and not caused by peculiar motions) the mean clustering length of galaxies in the three samples is r(_o) =(6.6±0.5)h(^-1) Mpc in the range 2<s<7h(^-1) Mpc and this is significantly larger than the r(_o) =5h(^-1) Mpc that was previously thought to apply to galaxies in this region of separation. At scales larger than -7h(^-1) Mpc the correlation function in the combined sample of the three surveys indicates that the galaxy distribution rapidly approaches homogeneity. Although there are some tentatively detected spatial scale lengths in the galaxy distribution at these larger scales, the main conclusion from the correlation function for these galaxies is that there is no evidence of large-scale clustering at the 2 sigma statistical significance level from separations of -10 to 100h(^-1) Mpc. Thus on the assumption that these galaxies trace the mass distribution this implies that the Universe is homogeneous to -15% at these scales. Finally, some new redshifts of galaxies were presented that were observed with the FLAIR spectrograph on the UK Schmidt telescope. These observations indicate that this instrument is capable of performing systematic redshift surveys of m(b(_J))<17(^m) galaxies with a completeness of -80% and with an accuracy in redshift velocity of ±150kms(^-1) rms. This will then pave the way for future large area redshift surveys in the southern hemisphere

The power of the “weak” and international organizations

By nearly every measure, power in the international system is concentrated, meaning that most states lack significant power resources. And yet international relations theory tends to focus on the behavior of great powers. This special issue instead explores the strategies that “weak” states use in the context of international organizations both to advance their interests and to resist pressure from stronger states. We define weakness as a relative lack of power across one or more dimensions. While the literature, to the extent it has focused on weak actors, has too often defined weakness solely in material terms, we adopt a broader conception that builds on the influential typology of power by Barnett and Duvall (Barnett and Duvall, 2005a, Barnett and Duvall, International Organization 59, 39–75, 2005b). A multidimensional conceptualization of power allows analysts to show how actors that are weak in one dimension (often material power) may be stronger on other dimensions, giving them greater capacity for action than is often recognized. From this framework we create a typology of “strategies of the weak” that emphasizes the agency of weaker actors to make the most of their positions. The contributions to the special issue, summarized here, illuminate and substantiate many of these strategies across a diverse range of international organizations, understood as both forums and actors. As the articles show, these alternative theoretical mechanisms help explain how and why seemingly weak states sometimes fare better than a simplistic assessment of their material capabilities might suggest. By deepening our understanding of weakness and how it influences state behavior, the volume advances our theoretical understanding of how power is built, wielded, and resisted in and through international organization

Early Urbanism in Europe The Trypillia Megasites of the Ukrainian Forest-Steppe

For over 60 years, the accepted view of cultural evolution was that the world's first cities developed in the Fertile Crescent in the 4th millennium BC. This view overlooks the emergence of a much neglected class of sites—the Trypillia megasites of the Ukrainian forest-steppe. The megasites were in fact larger and earlier than the Mesopotamian cities and demonstrate an alternative pathway towards cities without strong central administration and any later urban legacy. In this book, a team of international authors examines the hypothesis of independent Eastern European urbanism using the evidence gathered from the multi-disciplinary investigation of the megasite of Nebelivka

The effect of a diet with fructan-rich chicory roots on intestinal helminths and microbiota with special focus on Bifidobacteria and Campylobacter in piglets around weaning

The restrictions on the use of antibiotic and anthelmintic treatments in organic pig farming necessitate alternative non-medical control strategies. Therefore, the antibiotic and parasite-reducing effect of a fructan-rich (prebiotic) diet of dried chicory was investigated in free-ranging piglets. Approximately half of 67 piglets from 9 litters were experimentally infected with Ascaris suum and Trichuris suis in the suckling period (1 to 7 weeks of age) and 58 of the piglets were challenged daily with E. coli O138:F8 for 9 days after weaning to induce weaning diarrhoea. The litters were fed either chicory (30% DM) or a control diet. The effect of chicory on intestinal helminths, intestinal microbiota, especially Bifidobacteria and Campylobacter spp., and E. coli post-weaning diarrhoea was assessed. The weight gain of the piglets was not impaired significantly by chicory. The intestinal A. suum worm burden was reduced by 64% (P=0.034) in the chicory-fed piglets, whereas these same piglets had 63% more T. suis worms (P=0.016). Feeding with chicory elicited no changes among the main bacterial groups in ileum according to terminal restriction fragment length polymorphism (T-RFLP) analysis. However, the terminal-restriction fragment (T-RF) 208 bp, which may belong to Lachnospiraceae, was stimulated by the chicory feed (P=0.03), and T-RF 370 bp that matches Enterobacter belonging to the Enterobacteria was reduced (P=0.004). Additionally, chicory increased the level of Bifidobacteria (P=0.001) and the faecal Campylobacter excretion level was transitorily reduced in chicory-fed piglets at 7 weeks of age (P=0.029). Unfortunately, it was not possible to assess the effect of chicory on post-weaning diarrhoea as it did not develop. In conclusion, feeding piglets chicory around the time of weaning caused complex changes of the microbiota and parasite communities within the intestinal tract, and feeding piglets chicory may therefore serve as an animal-friendly strategy to control pathogens

Metabolic syndrome and cardiovascular disease following hematopoietic cell transplantation: screening and preventive practice recommendations from CIBMTR and EBMT

Metabolic syndrome (MetS) is a constellation of cardiovascular risk factors that increases the risk of cardiovascular disease, diabetes mellitus and all cause mortality. Long-term survivors of hematopoietic cell transplantation (HCT) have a substantial risk of developing MetS and cardiovascular disease, with the estimated prevalence of MetS being 31–49% among HCT recipients. Although MetS has not yet been proven to impact cardiovascular risk after HCT, an understanding of the incidence and risk factors for MetS in HCT recipients can provide the foundation to evaluate screening guidelines and develop interventions that may mitigate cardiovascular-related mortality. A working group was established through the Center for International Blood and Marrow Transplant Research and the European Group for Blood and Marrow Transplantation with the goal of reviewing literature and recommend practices appropriate to HCT recipients. Here we deliver consensus recommendations to help clinicians provide screening and preventive care for MetS and cardiovascular disease among HCT recipients. All HCT survivors should be advised of the risks of MetS and encouraged to undergo recommended screening based on their predisposition and ongoing risk factors

Cosmology from LOFAR Two-metre Sky Survey data release 2: angular clustering of radio sources

Covering ∼ 5600 deg2 to rms sensitivities of ∼70−100 μJy beam−1, the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS-DR2) provides the largest low-frequency (∼150 MHz) radio catalogue to date, making it an excellent tool for large-area radio cosmology studies. In this work, we use LoTSS-DR2 sources to investigate the angular two-point correlation function of galaxies within the survey. We discuss systematics in the data and an improved methodology for generating random catalogues, compared to that used for LoTSS-DR1, before presenting the angular clustering for ∼900 000 sources ≥1.5 mJy and a peak signal-to-noise ≥ 7.5 across ∼80 per cent of the observed area. Using the clustering, we infer the bias assuming two evolutionary models. When fitting angular scales of 0.5 ≤ θ < 5◦, using a linear bias model, we find LoTSS-DR2 sources are biased tracers of the underlying matter, with a bias of bC = 2.14+0.22 −0.20 (assuming constant bias) and bE(z = 0) = 1.79+0.15 −0.14 (for an evolving model, inversely proportional to the growth factor), corresponding to bE = 2.81+0.24 −0.22 at the median redshift of our sample, assuming the LoTSS Deep Fields redshift distribution is representative of our data. This reduces to bC = 2.02+0.17 −0.16 and bE(z = 0) = 1.67+0.12 −0.12 when allowing preferential redshift distributions from the Deep Fields to model our data. Whilst the clustering amplitude is slightly lower than LoTSS-DR1 (≥2 mJy), our study benefits from larger samples and improved redshift estimates

Abnormal cognition, sleep, EEG and brain metabolism in a novel knock-in Alzheimer mouse, PLB1

Peer reviewedPublisher PD

Cosmology from LOFAR Two-metre Sky Survey Data Release 2: Angular Clustering of Radio Sources

Covering ∼5600 deg2 to rms sensitivities of ∼70−100 μJy beam−1, the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS-DR2) provides the largest low-frequency (∼150 MHz) radio catalogue to date, making it an excellent tool for large-area radio cosmology studies. In this work, we use LoTSS-DR2 sources to investigate the angular two-point correlation function of galaxies within the survey. We discuss systematics in the data and an improved methodology for generating random catalogues, compared to that used for LoTSS-DR1, before presenting the angular clustering for ∼900,000 sources ≥1.5 mJy and a peak signal-to-noise ≥7.5 across ∼80% of the observed area. Using the clustering we infer the bias assuming two evolutionary models. When fitting {angular scales of 0.5≤θ&lt;5°, using a linear bias model, we find LoTSS-DR2 sources are biased tracers of the underlying matter, with a bias of bC=2.14+0.22−0.20 (assuming constant bias) and bE(z=0)=1.79+0.15−0.14 (for an evolving model, inversely proportional to the growth factor), corresponding to bE=2.81+0.24−0.22 at the median redshift of our sample, assuming the LoTSS Deep Fields redshift distribution is representative of our data. This reduces to bC=2.02+0.17−0.16 and bE(z=0)=1.67+0.12−0.12 when allowing preferential redshift distributions from the Deep Fields to model our data. Whilst the clustering amplitude is slightly lower than LoTSS-DR1 (≥2 mJy), our study benefits from larger samples and improved redshift estimates

Emergency Department Escalation in Theory and Practice: A Mixed-Methods Study Using a Model of Organizational Resilience

Study objective Escalation policies are used by emergency departments (EDs) when responding to an increase in demand (eg, a sudden inflow of patients) or a reduction in capacity (eg, a lack of beds to admit patients). The policies aim to maintain the ability to deliver patient care, without compromising safety, by modifying “normal” processes. The study objective is to examine escalation policies in theory and practice. Methods This was a mixed-method study involving a conceptual analysis of National Health Service escalation policies (n=12) and associated escalation actions (n=92), as well as a detailed ethnographic study of escalation in situ during a 16-month period in a large UK ED (n=30 observations). Results The conceptual analysis of National Health Service escalation policies found that their use requires the ability to dynamically reconfigure resources (staff and equipment), change work flow, and relocate patients. In practice, it was discovered that when the ED is under pressure, these prerequisites cannot always be attained. Instead, escalation processes were adapted to manage pressures informally. This adaptive need (“work as done”) was found to be incompletely specified in policies (“work as imagined”). Conclusion Formal escalation actions and their implementation in practice differed and varied in their effectiveness. Monitoring how escalation works in practice is essential in understanding whether and how escalation policies help to manage workload