Joining the 'discretionary homeless' : a reporter's decision to live in a Walmart parking lot and what he found

textI lived eight months of my final year of graduate school at the University of Texas at Austin as a homeless person, sleeping in my car. I parked overnight at various Walmart store locations across Austin. There was a group I have come to think of as the "discretionary homeless" who also regularly parked on Walmart lots. Being a member of the discretionary homeless means living in your car and being mobile - an option that many homeless people do not enjoy. Not unlike many members of the country's struggling middle and working classes, they may have had trouble finding steady work, failed to meet payments on a mortgage or opted not to deplete their financial resources to zero. It’s unclear how big a subset such people make up of the country's 610,000 homeless but what I learned from my reporting is that there are a sizable proportion of people who have made a conscious decision to become homeless. And perhaps it is a good prism through which one can examine these discretionary homeless -- to get a sense of the logic behind their decision, and to see how they are being handled or offered help. Discretionary homeless people are not likely to come in frequent contact with city residents and will likely continue staying on Walmart parking lots. We are generally self-sufficient and usually not a nuisance -- able to blend in with everyone else on the road and in public.Journalis

Epigenetics drive the evolution of sex chromosomes in animals and plants

We review how epigenetics affect sex chromosome evolution in animals and plants. In a few species, sex is determined epigenetically through the action of Y-encoded small RNAs. Epigenetics is also responsible for changing the sex of individuals through time, even in species that carry sex chromosomes, and could favour species adaptation through breeding system plasticity. The Y chromosome accumulates repeats that become epigenetically silenced which leads to an epigenetic conflict with the expression of Y genes and could accelerate Y degeneration. Y heterochromatin can be lost through ageing, which activates transposable elements and lowers male longevity. Y chromosome degeneration has led to the evolution of meiotic sex chromosome inactivation in eutherians (placentals) and marsupials, and dosage compensation mechanisms in animals and plants. X-inactivation convergently evolved in eutherians and marsupials via two independently evolved non-coding RNAs. In Drosophila, male X upregulation by the male specific lethal (MSL) complex can spread to neo-X chromosomes through the transposition of transposable elements that carry an MSL-binding motif. We discuss similarities and possible differences between plants and animals and suggest future directions for this dynamic field of research. This article is part of the theme issue ‘How does epigenetics influence the course of evolution?’info:eu-repo/semantics/publishedVersio

Rifting along the northern Gondwana margin and the evolution of the Rheic Ocean: A Devonian age for the El Castillo volcanic rocks (Salamanca, Central Iberian Zone)

Exposures of volcanic rocks (El Castillo) in the Central Iberian Zone near Salamanca, Spain, are representative of Paleozoic volcanic activity along the northern Gondwanan passive margin. Alkaline basalts and mafic volcaniclastic rocks of this sequence are structurally preserved in the core of the Variscan–Tamames Syncline. On the basis of the occurrence of graptolite fossils in immediately underlying strata, the El Castillo volcanics traditionally have been regarded as Lower Silurian in age. In contrast, most Paleozoic volcanic units in western Iberia are rift- elated mafic to felsic rocks emplaced during the Late Cambrian–Early Ordovician, and are attributed to the opening of the Rheic Ocean. We present new zircon U–Pb TIMS data from a mafic volcaniclastic rock within the El Castillo unit. These data yield a near-concordant, upper intercept age of 394.7±1.4 Ma that is interpreted to reflect a Middle Devonian (Emsian–Eifelian) age for the magmatism, demonstrating that the El Castillo volcanic rocks are separated from underlying lower Silurian strata by an unconformity. TheU–Pb age is coeval with a widespread extensional event in Iberia preserved in the form of a generalized paraconformity surface described in most of the Iberian Variscan realm. However, in the inner part of the Gondwanan platform, the Cantabrian Zone underwent a major, coeval increase in subsidence and the generation of sedimentary troughs. From this perspective, the eruption age reported here probably represents a discrete phase of incipient rifting along the southern flank of the Rheic Ocean. Paleogeographic reconstructions indicate that this rifting event was coeval with widespread orogeny and ridge subduction along the conjugate northern flank of the Rheic Ocean, the so called Acadian “orogeny”. We speculate that ridge subduction resulted in geodynamic coupling of the northern and southern flanks of the Rheic Ocean, and that the extension along the southern flank of the Rheic Ocean is a manifestation of slab pull along the northern flank. This scenario provides a uniform explanation for many features that form at ca. 395 Ma along the Gondwanan margin and has implications for the origin of the coeval oceanic Devonian mafic rocks currently exposed in the Variscan suture of NW Iberia

Identificación de competencias y características deseables en el profesorado de ciencias de EGB

This article offers the vision held by some groups of teachers on various qualities taken as important for a Science Teacher of Primary Education, as well as the opinion on to what extend those qualities are found in this type of teachers

Bases psicobiológicas de la adicción a cocaína

El principal mecanismo de acción de la cocaína es la inhibición de la recaptación de dopamina y noradrenalina, produciendo un aumento de estos neurotransmisores en la sinapsis. El consumo agudo de cocaína produce una serie de cambios bastante conocidos en el sistema cerebral de recompensa. Sin embargo, el consumo crónico, produce, además, otra serie de cambios a nivel molecular que llevan al sujeto desde una situación de consumo puntual, a una situación de dependencia. Se han propuesto diferentes teorías explicativas de este fenómeno como la sensibilización del incentivo, o la homeostasis y alostasis neuroquímica, planteamientos basados en el condicionamiento clásico y operante. Por otra parte, se ha señalado la intervención de diferentes moléculas y vías de segundos mensajeros, que producen, en última instancia, una serie de cambios neuronales mantenidos a muy largo plazo, probablemente permanentes, que se podrían relacionar con la vulnerabilidad a las recaídas, propia de la adicción a cocaína, incluso años después de abandonar el consumo

Redesign of the Jefferson Lab -300 kV DC Photo-Gun for High Bunch Charge Operations

Production of high bunch charge beams for the ElectronIon Collider (EIC) is a challenging task. High bunch charge (a few nC) electron beam studies at Jefferson Lab using an inverted insulator DC high voltage photo-gun showed evidence of space charge limitations starting at 0.3 nC, limiting the maximum delivered bunch charge to 0.7 nC for beam at -225 kV, 75 ps (FWHM) pulse width, and 1.64 mm (rms) laser spot size. The low extracted charge is due to the modest longitudinal electric field (Ez) at the photocathode leading to beam loss at the anode and downstream beam pipe. To reach the few nC high bunch charge goal, and to correct the beam deflection exerted by the non-symmetric nature of the inverted insulator photo-gun the existing photo-gun was modified. This contribution discusses the electrostatic design of the modified photo-gun obtained using CST Studio Suite’s electromagnetic field solver. Beam dynamics simulations performed using General Particle Tracer (GPT) with the resulting electrostatic field map obtained from the modified electrodes confirmed the validity of the new design

Detección de la garrapata exótica Amblyomma Varanense (acari: ixodidae) en especímenes importados de Varanus salvator (Squamata: Varanidae) en la Argentina

La importación de animales vivos, especialmente reptiles, ha contribuido al transporte e introducción de garrapatas exóticas en muchas regiones del mundo. Se describe el hallazgo de 11 especímenes (un macho, dos hembras y ocho ninfas) de Amblyomma varanense colectados de dos varanos acuáticos (Varanus salvator) importados legalmente desde Jakarta, Indonesia. Amblyomma varanense es una garrapata distribuida en las regiones zoogeográficas Oriental y de Australasia, y V. salvator se encuentra entre los principales hospedadores. Es necesario prevenir la introducción de garrapatas exóticas y microrganismos asociados, poniéndose en evidencia el riesgo que conlleva la importación de vertebrados exóticos.The importation of live animals, especially reptiles, has contributed to the transport and introduction of exotic ticks in many regions of the world. We describe the finding of 11 specimens (one male, two females and eight nymphs) of Amblyomma varanense collected from two common water monitors (Varanus salvator) legally imported from Jakarta, Indonesia. Amblyomma varanense is a tick distributed in the Eastern and Australasian zoogeographic regions, and V. salvator is among the main hosts. It is necessary to prevent the introduction of exotic ticks and associated microorganisms, highlighting the risk involved in the importation of exotic vertebrates.EEA RafaelaFil: Cicuttin, Gabriel L. Instituto de Zoonosis Luis Pasteur; ArgentinaFil: Wiemeyer, Guillermo. Ecoparque Buenos Aires (ex Jardín Zoológico de la Ciudad de Buenos Aires); ArgentinaFil: Perez, M.A.. Ecoparque Buenos Aires (ex Jardín Zoológico de la Ciudad de Buenos Aires); ArgentinaFil: Guglielmone, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Análisis arqueosismológico del conjunto arqueológico romano de Mulva- Munigua (Sevilla, España). Resultados preliminares

El conjunto arqueológico romano de Mulva-Munigua (Sevilla, España) presenta daños en las edificaciones que pueden ser interpretadas como resultado de la ocurrencia de un evento sísmico (Efectos Arqueológicos de los Terremotos: EAEs) a finales del siglo III A.D., fecha coincidente con el inicio del periodo de declive económico de este asentamiento romano. Para intentar establecer el posible origen sísmico de las deformaciones, se ha procedido al inventario y análisis de las estructuras deformadas presentes en el yacimiento. No obstante, algunas de estas deformaciones también se pueden interpretar como resultado de procesos gravitaciones asociados a la ladera Este de la colina sobre la que se sitúa parte del yacimiento. Las direcciones de máxima deformación (ey) obtenidas del análisis de EAEs indica dos direcciones preferentes de la deformación (o movimiento preferente del terreno): NNO-SSE y ENEOSO. Aunque los datos presentan una dispersión importante, se puede establecer que la orientación principal NNO-SSE es compatible con un evento sísmico situado en el borde norte del Valle del Guadalquivir. La orientación ENE-OSO podría relacionarse con un evento posterior, o más seguramente con procesos de ladera de carácter cosísmico o no.The Roman archaeological site of Mulva-Munigua (Sevilla, Spain) displays building damage features suggesting a seismic origin (Earthquake Archaeological Effects: EAEs). The proposed seismic event could be tentatively dated in the late 3rd century AD, coinciding with the beginning of the economic fall of the Roman Empire at Iberia. However, some of the recorded EAEs can be also interpreted as a result of intervening slope movements in the eastern hillslope of this roman site. The inventory and analysis of the proposed EAEs make possible to discern between seismic oriented damage and other causes. In spite of the data show a significant dispersion, their analysis result in two different orientations of maximum deformation (ey) or preferential ground movement: NNW-SSE and ENE-WSW. The main ey orientation (NNW-SSE) can be tentatively related to a seismic event occurred in the environs of the northern border of the Guadalquivir Depression. The secondary orientation (ENE-WSW) can be interpreted as a consequence of latter slope movements triggered (or not) by other ancient earthquakes

The Rotterdam Scan Study: design update 2016 and main findings

Imaging plays an essential role in research on neurological diseases in the elderly. The Rotterdam Scan Study was initiated as part of the ongoing Rotterdam Study with the aim to elucidate the causes of neurological disease by performing imaging of the brain in a prospective population-based setting. Initially, in 1995 and 1999, random subsamples of participants from the Rotterdam Study underwent neuroimaging, whereas from 2005 onwards MRI has been implemented into the core protocol of the Rotterdam Study. In this paper, we discuss the background and rationale of the Rotterdam Scan Study. Moreover, we describe the imaging protocol, image post-processing techniques, and the main findings to date. Finally, we provide recommendations for future research, which will also be topics of investigation in the Rotterdam Scan Study

Forgotten giants: Robust climate signal in pollarded trees

Producción CientíficaTree ring records are among the most valuable resources to create high-resolution climate reconstructions. Most climate reconstructions are based on old trees growing in inaccessible mountainous areas with low human activity. Therefore, reconstruction of climate conditions in lowlands is usually based on data from distant mountains. Albeit old trees can be common in humanized areas, they are not used for climate reconstructions. Pollarding was a common traditional management in Europe that enabled trees to maintain great vitality for periods exceeding the longevity of unmanaged trees. We evaluate the potential of pollarded deciduous oaks to record past climate signal. We sampled four pollarded woodlands in Central Spain under continental Mediterranean climate. We hypothesized that pollarded trees have a strong response to water availability during current period without pollarding management, but also in the period under traditional management if pruning was asynchronous among trees. Moreover, we hypothesized that if climate is a regional driver of oak secondary growth, chronologies from different woodlands will be correlated. Pollard oaks age exceeded 500 years with a strong response to Standardized Precipitation-Evapotranspiration Index (SPEI) from 9 to 11 months. Climate signal was exceptionally high in three of the sites (r2 = 0.443–0.655) during low management period (1962–2022). The largest fraction of this climate signal (≈70 %) could be retrieved during the traditional management period (1902–1961) in the three sites where pollarding was asynchronous. Chronologies were significantly correlated since the 19th century for all the studied period, highlighting a shared climate forcing. We identified critical points to optimize pollard tree sampling schema. Our results show the enormous potential of pollarded woodlands to reconstruct hydroclimate conditions in the Mediterranean with a fine spatial grain. Studying pollarded trees is an urgent task, since the temporal window to retrieve the valuable information in pollarded trees is closing as these giants collapse and their wood rots.Junta de Castilla y León-Consejería de Educación [IR2020-1-UVA08; VA171P20]EU LIFE Soria Forest Adapt [LIFE19 CCA/ES/001181]Ministerio de Ciencia e Innovación - AEI (IJC2019-040571-I)Ministerio de Ciencia e Innovación - AEI (PRE2018-084106