The Size and Shape of Local Voids

We study the size and shape of low density regions in the local universe which we identify in the smoothed density field of the PSCz flux limited IRAS galaxy catalogue. After quantifying the systematic biases that enter in the detection of voids using our data set and method, we identify, using a smoothing length of 5 $h^{-1}$ Mpc, 14 voids within 80 $h^{-1}$ Mpc and using a smoothing length of 10 $h^{-1}$ Mpc, 8 voids within 130 $h^{-1}$ Mpc. We study the void size distribution and morphologies and find that there is roughly an equal number of prolate and oblate-like spheroidal voids. We compare the measured PSCz void shape and size distributions with those expected in six different CDM models and find that only the size distribution can discriminate between models. The models preferred by the PSCz data are those with intermediate values of $\sigma_{8} (\simeq 0.83)$, independent of cosmology.Comment: final version, Accepted in MNRA

CARGC Briefs Volume I: ISIS Media

The essays that comprise CARGC Briefs Volume I: ISIS Media began their lives as presentations at a small, by-invitation workshop, “Emerging Work on Communicative Dimensions of Islamic State,” held on May 3-4, 2017 at the Center for Advanced Research in Global Communication at the Annenberg School for Communication. Consistent with CARGC’s mission to mentor early-career scholars, the workshop was a non-public event featuring graduate students, some affiliated with the Jihadi Networks of Communication and CultureS (JINCS) research group at CARGC, and others from around the United States and the world, in addition to postdocs and faculty members. Parameters were purposefully broad to encourage independent thought and intellectual exploration: contributors were asked to write short essays focusing on any single aspect of Islamic State that was part of their research. The result is a group of fascinating essays: using mostly primary sources (textual, visual, or audio-visual), examining several media platforms and modalities, considering multiple levels of theoretical deployment and construction, and shedding light on various aspects of Islamic State communication against the broad back drop of history, ideology and geopolitics, the following include some of the most innovative approaches to Islamic State to date, and promise a wave of fresh voices on one of the most important challenges to global order.https://repository.upenn.edu/cargc_briefs/1000/thumbnail.jp

Unveiling transportation disparities: investigating accessibility gaps in metropolitan cities using GIS—a case study of Alexandria, Egypt

IntroductionPublic transportation is essential to reduce pollution and traffic congestion in urban areas. However, in densely populated regions like Alexandria, characterized by high population density and limited road infrastructure, accessibility to diverse transportation options is crucial.MethodsThis study investigates the accessibility of public transportation modes, including railways and buses, and their interaction with informal transit. Questioning if public transportation alone will be sufficient for pedestrians or if the presence of informal transit is crucial, and whether all residents of Alexandria have their rightful accessibility for different transport modes, the goal was to establish an efficient and interconnected transportation network. A survey was conducted in cooperation with Transport for Cairo to investigate all transport routes throughout Alexandria, further using ArcGIS Pro to identify gaps in public transportation coverage.ResultsFindings revealed that public transportation alone is insufficient due to limited bus and railway coverage because of their fixed linear routes. Informal transit, like microbuses, plays a vital role in filling these gaps.DiscussionThe study emphasizes the need for a comprehensive and sustainable transportation network that considers both formal and informal transit. These insights can guide policymakers and urban planners in improving public transportation in Alexandria and similar cities worldwide

Clonality of HTLV-2 in natural infection

Human T-lymphotropic virus type 1 (HTLV-1) and type 2 (HTLV-2) both cause lifelong persistent infections, but differ in their clinical outcomes. HTLV-1 infection causes a chronic or acute T-lymphocytic malignancy in up to 5% of infected individuals whereas HTLV-2 has not been unequivocally linked to a T-cell malignancy. Virus-driven clonal proliferation of infected cells both in vitro and in vivo has been demonstrated in HTLV-1 infection. However, T-cell clonality in HTLV-2 infection has not been rigorously characterized. In this study we used a high-throughput approach in conjunction with flow cytometric sorting to identify and quantify HTLV-2-infected T-cell clones in 28 individuals with natural infection. We show that while genome-wide integration site preferences in vivo were similar to those found in HTLV-1 infection, expansion of HTLV-2-infected clones did not demonstrate the same significant association with the genomic environment of the integrated provirus. The proviral load in HTLV-2 is almost confined to CD8+ T-cells and is composed of a small number of often highly expanded clones. The HTLV-2 load correlated significantly with the degree of dispersion of the clone frequency distribution, which was highly stable over ∼8 years. These results suggest that there are significant differences in the selection forces that control the clonal expansion of virus-infected cells in HTLV-1 and HTLV-2 infection. In addition, our data demonstrate that strong virus-driven proliferation per se does not predispose to malignant transformation in oncoretroviral infections

Globalization and the diffusion of ideas: why we should acknowledge the roots of mainstream ideas in global health

Although globalization has created ample opportunities and spaces to share experiences and information, the diffusion of ideas, especially in global health, is primarily influenced by the unequal distribution of economic, political and scientific powers around the world. These ideas in global health are generally rooted in High-Income Countries (HICs), and then reach Low- and Middle-Income Countries (LMICs). We argue that acknowledging and addressing this invisible trend would contribute to a greater degree of open discussions in global health. This is expected to favor innovative, alternative, and culturally sound solutions for persistent health problems and reducing inequitie

Remodelling by early-life stress of NMDA receptor-dependent synaptic plasticity in a gene-environment rat model of depression.

An animal model of depression combining genetic vulnerability and early-life stress (ELS) was prepared by submitting the Flinders Sensitive Line (FSL) rats to a standard paradigm of maternal separation. We analysed hippocampal synaptic transmission and plasticity in vivo and ionotropic receptors for glutamate in FSL rats, in their controls Flinders Resistant Line (FRL) rats, and in both lines subjected to ELS. A strong inhibition of long-term potentiation (LTP) and lower synaptic expression of NR1 subunit of the NMDA receptor were found in FSL rats. Remarkably, ELS induced a remodelling of synaptic plasticity only in FSL rats, reducing inhibition of LTP; this was accompanied by marked increase of synaptic NR1 subunit and GluR2/3 subunits of AMPA receptors. Chronic treatment with escitalopram inhibited LTP in FRL rats, but this effect was attenuated by prior ELS. The present results suggest that early gene-environment interactions cause lifelong synaptic changes affecting functional and molecular aspects of plasticity, partly reversed by antidepressant treatments

Tumor suppressor p53 binds with high affinity to CTG-CAG trinucleotide repeats and induces topological alterations in mismatched duplexes

DNA binding is central to the ability of p53 to function as a tumor suppressor. In line with the remarkable functional versatility of p53, which can act on DNA as a transcription, repair, recombination, replication, and chromatin accessibility factor, the modes of p53 interaction with DNA are also versatile. One feature common to all modes of p53-DNA interaction is the extraordinary sensitivity of p53 to the topology of its target DNA. Whereas the strong impact of DNA topology has been demonstrated for p53 binding to sequence-specific sites or to DNA lesions, the possibility that DNA structure-dependent recognition may underlie p53 interaction with other types of DNA has not been addressed until now. We demonstrate for the first time that conformationally flexible CTG·CAG trinucleotide repeats comprise a novel class of p53-binding sites targeted by p53 in a DNA structure-dependent mode in vitro and in vivo. Our major finding is that p53 binds to CTG·CAG tracts by different modes depending on the conformation of DNA. Although p53 binds preferentially to hairpins formed by either CTG or CAG strands, it can also bind to linear forms of CTG·CAG tracts such as canonic B DNA or mismatched duplex. Intriguingly, by binding to a mismatched duplex p53 can induce further topological alterations in DNA, indicating that p53 may act as a DNA topology-modulating factor

Long-term effects of chronic light pollution on seasonal functions of European blackbirds (turdus merula)

Light pollution is known to affect important biological functions of wild animals, including daily and annual cycles. However, knowledge about long-term effects of chronic exposure to artificial light at night is still very limited. Here we present data on reproductive physiology, molt and locomotor activity during two-year cycles of European blackbirds (Turdus merula) exposed to either dark nights or 0.3 lux at night. As expected, control birds kept under dark nights exhibited two regular testicular and testosterone cycles during the two-year experiment. Control urban birds developed testes faster than their control rural conspecifics. Conversely, while in the first year blackbirds exposed to light at night showed a normal but earlier gonadal cycle compared to control birds, during the second year the reproductive system did not develop at all: both testicular size and testosterone concentration were at baseline levels in all birds. In addition, molt sequence in light-treated birds was more irregular than in control birds in both years. Analysis of locomotor activity showed that birds were still synchronized to the underlying light-dark cycle. We suggest that the lack of reproductive activity and irregular molt progression were possibly the results of i) birds being stuck in a photorefractory state and/or ii) chronic stress. Our data show that chronic low intensities of light at night can dramatically affect the reproductive system. Future studies are needed in order to investigate if and how urban animals avoid such negative impact and to elucidate the physiological mechanisms behind these profound long-term effects of artificial light at night. Finally we call for collaboration between scientists and policy makers to limit the impact of light pollution on animals and ecosystems

The Cosmic Infrared Background: Measurements and Implications

The cosmic infrared background records much of the radiant energy released by processes of structure formation that have occurred since the decoupling of matter and radiation following the Big Bang. In the past few years, data from the Cosmic Background Explorer mission provided the first measurements of this background, with additional constraints coming from studies of the attenuation of TeV gamma-rays. At the same time there has been rapid progress in resolving a significant fraction of this background with the deep galaxy counts at infrared wavelengths from the Infrared Space Observatory instruments and at submillimeter wavelengths from the Submillimeter Common User Bolometer Array instrument. This article reviews the measurements of the infrared background and sources contributing to it, and discusses the implications for past and present cosmic processes.Comment: 61 pages, incl. 9 figures, to be published in Annual Reviews of Astronomy and Astrophysics, 2001, Vol. 3