Context.
Asteroids in comet-like orbits (ACOs) consist of asteroids and dormant comets. Due to their similar appearance, it is challenging to distinguish dormant comets from ACOs via general ...telescopic observations. Surveys for discriminating dormant comets from the ACO population have been conducted via spectroscopy or optical and mid-infrared photometry. However, they have not been conducted through polarimetry.
Aims.
We conducted the first polarimetric research of ACOs.
Methods.
We conducted a linear polarimetric pilot survey for three ACOs: (944) Hidalgo, (3552) Don Quixote, and (331471) 1984 QY1. These objects are unambiguously classified into ACOs in terms of their orbital elements (i.e., the Tisserand parameters with respect to Jupiter
T
J
significantly less than 3). Three ACOs were observed by the 1.6 m Pirka Telescope from UT 2016 May 25 to UT 2019 July 22 (13 nights).
Results.
We found that Don Quixote and Hidalgo have polarimetric properties similar to comet nuclei and D-type asteroids (optical analogs of comet nuclei). However, 1984 QY1 exhibited a polarimetric property consistent with S-type asteroids. We conducted a backward orbital integration to determine the origin of 1984 QY1, and found that this object was transported from the main belt into the current comet-like orbit via the 3:1 mean motion resonance with Jupiter.
Conclusions.
We conclude that the origins of ACOs can be more reliably identified by adding polarimetric data to the color and spectral information. This study would be valuable for investigating how the ice-bearing small bodies distribute in the inner Solar System.
Full text
Available for:
FMFMET, NUK, UL, UM, UPUK
Miguel Hesayne se desempeñó como obispo de la Diócesis de Viedma entre los años 1975 y 1995. Durante ese periodo, Hesayne desarrolló un proyecto pastoral pensado desde la construcción de una nueva ...Iglesia que se diseñó desde el Sínodo diocesano convocado en los albores de la democracia (1983-1984). En el presente artículo nos proponemos recorrer los comienzos de esa Iglesia postsinodal a través del análisis de la campaña una oveja para mi hermano , de la revista De Pie y del proyecto de Promotores Sociales, iniciativas que fueron desplegándose en el contexto de la nevada de 1984 y que visibilizan la concepción de Hesayne en torno al rol que debería asumir la nueva Iglesia rionegrina frente a las cuestiones sociales. Para dicha investigación hemos relevado documentos, cartas y publicaciones periódicas del archivo de la diócesis de Viedma y del archivo personal de un sacerdote cercano a Hesayne. También realizamos entrevistas en profundidad a referentes de comunidades indígenas; sacerdotes que acompañaron el proyecto del obispado en sus inicios; y a históricos funcionarios del INTA.
Different times, different fears. While writing 1984, Georges Orwell saw the ghosts of totalitarism arise in the wake of WWII. A dark future for a nightmarish world, in which the individual is ...dissolved in the community, love is absent, obedience is a duty and surveillance is total. If the dystopias following Orwell were each interested in a particular aspect of social ideals (happiness, family, for example), 2084 is certainly 1984’s clearest heir. However, the world described by Boualem Sansal is in appearance very different in its theocracy and its lack of technology. Nevertheless, my purpose will be to show that the dystopian novel by Boualem Sansal is a direct sequel of 1984 and that this mutation of Orwell’s dystopian universe is an alarm signal to a declining Europe.
•Autistic individuals prevented from effectively participating in custody process.•Barriers to communication affect interactions between officers and autistic detainees.•The custody environment ...creates sensory difficulties for autistic detainees.•Officers are prevented from providing effective support due to demands of custody.•Changes to practice, the custody environment and policy will help improve support.
Research suggests that autistic individuals may be more likely to come into contact with police and have more negative experiences in police custody. However, limited information about the difficulties they experience during the custody process is available.
This study explores the experiences of autistic individuals and officers during a walkthrough of the custody process to identify specific difficulties in these encounters and what support is needed to overcome these.
A participative walkthrough method was developed to provide autistic individuals and officers an interactive opportunity to identify areas where further support in the custody process was needed. Two autistic participants and three officers took part in the study.
Autistic participants reported negative experiences due to: i) the emotional impact of the physical setting and custody process ii) communication barriers leading to increased anxiety and iii) exposure to sensory demands. Officers highlighted three factors which limit their ability to support autistic individuals effectively: i) the custody context ii) barriers to communication and iii) knowledge and understanding of autism.
Adjustments are needed to the custody process and environment to support interactions between autistic individuals and officers and improve the overall wellbeing of autistic individuals.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Clinical and experimental data suggest that fronto-cortical GABAergic deficits contribute to the pathophysiology of major depressive disorder (MDD). To further test this hypothesis, we used a well ...characterized rat model for depression and examined the effect of stress on GABAergic neuron numbers and GABA-mediated synaptic transmission in the medial prefrontal cortex (mPFC) of rats. Adult male Wistar rats were subjected to 9-weeks of chronic mild stress (CMS) and based on their hedonic-anhedonic behavior they were behaviorally phenotyped as being stress-susceptible (anhedonic) or stress-resilient. Post mortem quantitative histopathology was used to examine the effect of stress on parvalbumin (PV)-, calretinin- (CR), calbindin- (CB), cholecystokinin- (CCK), somatostatin-(SST) and neuropeptide Y-positive (NPY+) GABAergic neuron numbers in all cortical subareas of the mPFC (anterior cingulate (Cg1), prelimbic (PrL) and infralimbic (IL) cortexes).
, whole-cell patch-clamp recordings from layer II-III pyramidal neurons of the ventral mPFC was used to examine GABAergic neurotransmission. The cognitive performance of the animals was assessed in a hippocampal-prefrontal-cortical circuit dependent learning task. Stress exposure reduced the number of CCK-, CR- and PV-positive GABAergic neurons in the mPFC, most prominently in the IL cortex. Interestingly, in the stress-resilient animals, we found higher number of neuropeptide Y-positive neurons in the entire mPFC. The electrophysiological analysis revealed reduced frequencies of spontaneous and miniature IPSCs in the anhedonic rats and decreased release probability of perisomatic-targeting GABAergic synapses and alterations in GABA
receptor mediated signaling. In turn, pyramidal neurons showed higher excitability. Anhedonic rats were also significantly impaired in the object-place paired-associate learning task. These data demonstrate that long-term stress results in functional and structural deficits of prefrontal GABAergic networks. Our findings support the concept that fronto-limbic GABAergic dysfunctions may contribute to emotional and cognitive symptoms of MDD.
Mark Zuckerberg, the CEO of Meta, is one of the richest and most powerful men in the world. His position seems unassailable, so why does he run his business empire as though it’s under constant ...threat?
In many coastal areas, marine ecosystems have shifted into contrasting states having reduced ecosystem services (hereafter called degraded). Such degraded ecosystems may be slow to revert to their ...original state due to new ecological feedbacks that reinforce the degraded state. A better understanding of the way human actions influence the strength and direction of feedbacks, how different feedbacks could interact, and at what scales they operate, may be necessary in some cases for successful management of marine ecosystems. Here we synthesize interactions of critical feedbacks of the degraded states from six globally distinct biomes: coral reefs, kelp forests, seagrass beds, shallow soft sediments, oyster reefs, and coastal pelagic food webs. We explore to what extent current management captures these feedbacks and propose strategies for how and when (that is, windows of opportunity) to influence feedbacks in ways to break the resilience of the degraded ecosystem states. We conclude by proposing some challenges for future research that could improve our understanding of these issues and emphasize that management of degraded marine states will require a broad social—ecological approach to succeed.
•Juvenile brown trout were exposed to n-TiO2, PCB77, and n-TiO2-PCB77 mixtures via the diet.•The presence of n-TiO2 in the test diet affected PCB77 availability.•Dietary co-exposure to n-TiO2 and ...PCB77 led to combination effects on intestinal tight junction protein (zo-1) expression.•An object resembling n-TiO2 was imaged inside the Space of Disse of a liver sinusoid suggesting NP transport to the liver.•n-TiO2 had a potentiating effect on PCB77-induced biomarker responses in the liver.
Titanium dioxide nanoparticles (n-TiO2) are among the man-made nanomaterials that are predicted to be found at high concentrations in the aquatic environment. There, they likely co-exist with other chemical pollutants. Thus, n-TiO2 and other chemical pollutants can be taken up together or accumulate independently from each other in prey organisms of fish. This can lead to dietary exposure of fish to n-TiO2-chemical pollutant mixtures. In this study, we examine if simultaneous dietary exposure to n-TiO2 and 3,3’,4,4’-Tetrachlorobiphenyl (PCB77) –used as a model compound for persistent organic pollutants with dioxin-like properties– can influence the uptake and toxicological response elicited by the respective other substance. Juvenile brown trout (Salmo trutta) were fed custom-made food pellets containing n-TiO2, PCB77 or n-TiO2+PCB77 mixtures for 15 days. Ti and PCB77 concentrations in the liver were measured by ICP-MS and GC–MS, respectively. Besides, n-TiO2 uptake was assessed using TEM. Combination effects on endpoints specific for PCB77 (i.e., cytochrome P450 1A (CYP1A) induction) and endpoints shared by both PCB77 and n-TiO2 (i.e., oxidative stress-related parameters) were measured in intestine and liver using RT-qPCR and enzyme activity assays. The results show that genes encoding for proteins/enzymes essential for tight junction function (zo-1) and ROS elimination (sod-1) were significantly upregulated in the intestine of fish exposed to n-TiO2 and PCB77 mixtures, but not in the single-substance treatments. Besides, n-TiO2 had a potentiating effect on PCB77-induced CYP1A and glutathione reductase (GR) expression/enzyme activity in the liver. This study shows that simultaneous dietary exposure to nanomaterials and traditional environmental pollutants might result in effects that are larger than observed for the substances alone, but that understanding the mechanistic basis of such effects remains challenging.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
