Evolution and complexity: the double-edged sword

We attempt to provide a comprehensive answer to the question of whether, and when, an arrow of complexity emerges in Darwinian evolution. We note that this expression can be interpreted in different ways, including a passive, incidental growth, or a pervasive bias towards complexification. We argue at length that an arrow of complexity does indeed occur in evolution, which can be most reasonably interpreted as the result of a passive trend rather than a driven one. What, then, is the role of evolution in the creation of this trend, and under which conditions will it emerge? In the later sections of this article we point out that when certain proper conditions (which we attempt to formulate in a concise form) are met, Darwinian evolution predictably creates a sustained trend of increase in maximum complexity (that is, an arrow of complexity) that would not be possible without it; but if they are not, evolution will not only fail to produce an arrow of complexity, but may actually prevent any increase in complexity altogether. We conclude that, with regard to the growth of complexity, evolution is very much a double-edged sword

Violent radicalization during the COVID-19 pandemic: at the intersection of gender, conspiracy theories and psychological distress

The COVID-19 pandemic continues to pose a threat to health, economic stability and collective functioning. The related upsurge in psychological distress has fuelled the emergence of conspiracy theories regarding the origins of the virus. Worldwide, there is mounting evidence that these narratives have increased stigma and discrimination against diverse ethnic, age and occupational groups. However, the role of gender in the dynamics weaving together psychological distress, conspiracy theories and legitimation of violence toward other groups is still unknown. This paper addresses this knowledge gap, analysing a Canadian interprovincial survey conducted in November 2020. In total, 6003 individuals aged 18-35 years residing in large Canadian cities responded to an online survey administered in English and French between October 16 and November 17, 2020. A total of 4928 individuals with complete data on support for violent radicalization (VR), psychological distress, and endorsement of COVID-19 conspiracy theories were included in the analysis. This study indicates that for young Canadian adults, gender, endorsement of COVID-19 conspiracy theories and psychological distress, as measured by the Hopkins Symptom Checklist-25 (HSCL-25), have an interaction effect on support for VR, as measured by both the Sympathy for Violent Radicalization Scale (SyfoR) and the Radicalism Intention Scale (RIS) (both p-values <.001). While the magnitude of the association between support for VR and endorsement of COVID-19 conspiracy theories is greatest among individuals with scores of psychological distress above the clinical cut-off, there is a significant association between scores on support for VR and endorsement of COVID-19 conspiracy theories in both women and men, both above and below the psychological distress cut-off of the HSCL-25. Effective strategies to mitigate the relationship between violent radicalization and pandemic-related psychological distress must explicitly address gender differences in expression and management of psychological distress

A simple method for the determination of lipid composition of human bile

The Entero-Test, a device for easy sampling of gastrointestinal contents, including bile, has been used for determination of biliary lipid composition. The device consists of a weighted gelatin capsule containing 140 cm of a highly absorbent nylon line. The capsule is swallowed while one end of the string is taped to the face. After 3.5 h, when the line has reached the duodenum, gallbladder contraction is stimulated by intramuscular administration of ceruletide. The line is pulled out, and the last 15 cm are eluted four times in methanol. Total bile acids (by 3 alpha-hydroxysteroid-dehydrogenase assay), individual bile acids (by high performance liquid chromatography), phospholipids (by assay of lipid-soluble phosphorus), and cholesterol (by gas-liquid chromatography) are determined in the eluate. Tests in vitro demonstrated no preferential binding and a good recovery of biliary lipids from the thread. Similar values of biliary cholesterol saturation were obtained by means of duodenal intubation and of the Entero-Test in a series of 12 subjects (r = 0.952). In 5 subjects, individual bile acids were also measured and were found to be similar with both techniques (r = 0.948). When the test was repeated over 3 days in a series of 7 subjects, biliary cholesterol saturation was found to be remarkably reproducible (CV = 7.6%). Thus, the Entero-Test is a convenient technique for the determination of biliary lipid composition, which can be particularly useful in longitudinal studies

Violent radicalization during the COVID-19 pandemic: at the intersection of gender, conspiracy theories and psychological distress

The COVID-19 pandemic continues to pose a threat to health, economic stability and collective functioning. The related upsurge in psychological distress has fuelled the emergence of conspiracy theories regarding the origins of the virus. Worldwide, there is mounting evidence that these narratives have increased stigma and discrimination against diverse ethnic, age and occupational groups. However, the role of gender in the dynamics weaving together psychological distress, conspiracy theories and legitimation of violence toward other groups is still unknown. This paper addresses this knowledge gap, analysing a Canadian interprovincial survey conducted in November 2020. In total, 6003 individuals aged 18-35 years residing in large Canadian cities responded to an online survey administered in English and French between October 16 and November 17, 2020. A total of 4928 individuals with complete data on support for violent radicalization (VR), psychological distress, and endorsement of COVID-19 conspiracy theories were included in the analysis. This study indicates that for young Canadian adults, gender, endorsement of COVID-19 conspiracy theories and psychological distress, as measured by the Hopkins Symptom Checklist-25 (HSCL-25), have an interaction effect on support for VR, as measured by both the Sympathy for Violent Radicalization Scale (SyfoR) and the Radicalism Intention Scale (RIS) (both p-values <.001). While the magnitude of the association between support for VR and endorsement of COVID-19 conspiracy theories is greatest among individuals with scores of psychological distress above the clinical cut-off, there is a significant association between scores on support for VR and endorsement of COVID-19 conspiracy theories in both women and men, both above and below the psychological distress cut-off of the HSCL-25. Effective strategies to mitigate the relationship between violent radicalization and pandemic-related psychological distress must explicitly address gender differences in expression and management of psychological distress

Journal Staff

We present the first measurements of the differential cross section d sigma/dp(T)(gamma) for the production of an isolated photon in association with at least two b-quark jets. The measurements consider photons with rapidities vertical bar y(gamma)vertical bar &lt; 1.0 and transverse momenta 30 &lt; p(T)(gamma) &lt; 200 GeV. The b-quark jets are required to have p(T)(jet) &gt; 15 GeVand vertical bar y(jet)vertical bar &lt; 1.5. The ratio of differential production cross sections for gamma + 2 b-jets to gamma + b-jet as a function of p(T)(gamma) is also presented. The results are based on the proton-antiproton collision data at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The measured cross sections and their ratios are compared to the next- to- leading order perturbative QCD calculations as well as predictions based on the k(T)- factorization approach and those from the sherpa and pythia Monte Carlo event generators

Search for B0→π0π0B^{0}\to \pi^{0}\pi^{0} Decay

We have searched for the charmless hadronic decay of B0 mesons into two neutral pions. Using 9.13fb^-1 taken at the Upsilon(4S) with the CLEO detector, we obtain an improved upper limit for the branching fraction BR(B0-->pi0pi0) < 5.7*10^-6 at the 90% confidence level.Comment: pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Search for Zgamma events with large missing transverse energy in ppbar collisions at sqrt(s)=1.96 TeV

We present the first search for supersymmetry (SUSY) in Zgamma final states with large missing transverse energy using data corresponding to an integrated luminosity of 6.2 fb-1 collected with the D0 experiment in ppbar collisions at sqrt(s)=1.96 TeV. This signature is predicted in gauge-mediated SUSY-breaking models, where the lightest neutralino is the next-to-lightest supersymmetric particle (NLSP) and is produced in pairs, possibly through decay from heavier supersymmetric particles. The NLSP can decay either to a Z boson or a photon and an associated gravitino that escapes detection. We exclude this model at the 95% C.L. for SUSY breaking scales of Lambda < 87 TeV, corresponding to neutralino masses of < 151 GeV.Comment: submitted to Phys. Rev. Let

Precise measurement of the top quark mass in the dilepton channel at D0

We measure the top quark mass (mt) in ppbar collisions at a center of mass energy of 1.96 TeV using dilepton ttbar->W+bW-bbar->l+nubl-nubarbbar events, where l denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider. We obtain mt = 174.0 +- 1.8(stat) +- 2.4(syst) GeV, which is in agreement with the current world average mt = 173.3 +- 1.1 GeV. This is currently the most precise measurement of mt in the dilepton channel.Comment: 7 pages, 4 figure

Measurement of Leptonic Asymmetries and Top Quark Polarization in ttbar Production

We present measurements of lepton (l) angular distributions in ttbar -> W+ b W- b -> l+ nu b l- nubar bbar decays produced in ppbar collisions at a center-of-mass energy of sqrt(s)=1.96TeV, where l is an electron or muon. Using data corresponding to an integrated luminosity of 5.4fb^-1, collected with the D0 detector at the Fermilab Collider, we find that the angular distributions of l- relative to anti-protons and l+ relative to protons are in agreement with each other. Combining the two distributions and correcting for detector acceptance we obtain the forward-backward asymmetry A^l_FB = (5.8 +- 5.1(stat) +- 1.3(syst))%, compared to the standard model prediction of A^l_FB (predicted) = (4.7 +- 0.1)%. This result is further combined with the measurement based on the analysis of the l+jets final state to obtain A^l_FB = (11.8 +- 3.2)%. Furthermore, we present a first study of the top-quark polarization.Comment: submitted versio