606 research outputs found
Surface Studies of Duodenal Lesions Induced by Thoracic Irradiation
Acute duodenal ulcers are produced in mice as a remote ( abscopal ) effect of irradiation to the lower mediastinum. Such lesions have been examined with scanning electron microscopy at 5, 8 and 28 days after irradiation with 18 Gy of X-rays. All the ulcers occur within the first 1 cm long segment of the duodenum which is endowed with Brunner\u27s glands. The single lesions vary in size, shape and position. The damaged area often includes much of the duodenal circumference and is distinguished by conical or rudimentary villi, or even by the complete absence of villi. In contrast, around the periphery of the ulcer the villi are mostly vertical. Although the floor of these lesions appears to be covered with a continuous epithelial layer, during the first 4 weeks after irradiation the severity of the focal duodenal damage seems to increase gradually with time. The lesions have been compared with specimens from unirradiated mice and also with samples taken 3 days after partial thoracic irradiation when little damage is seen. The pattern of fully developed duodenal lesions differs greatly from that seen after direct irradiation where damage has not included localised ulceration in the samples of jejunum so far examined.
The lesions induced by partial thoracic irradiation may be related to radiation injury to vascular or autonomic nerve targets in the lower mediastinum. Such injury could result in malfunction of the pyloric sphincter or could alter the secretion by Brunner\u27s glands and thus lead to duodenal ulceration
Another short-burst host galaxy with an optically obscured high star formation rate: The case of GRB 071227
We report on radio continuum observations of the host galaxy of the short
gamma-ray burst 071227 (z=0.381) with the Australia Telescope Compact Array
(ATCA). We detect the galaxy in the 5.5 GHz band with an integrated flux
density of Fnu = 43 +/- 11 microJy, corresponding to an unobscured
star-formation rate (SFR) of about 24 Msun/yr, forty times higher than what was
found from optical emission lines. Among the ~30 well-identified and studied
host galaxies of short bursts this is the third case where the host is found to
undergo an episode of intense star formation. This suggests that a fraction of
all short-burst progenitors hosted in star-forming galaxies could be physically
related to recent star formation activity, implying a relatively short merger
time scale.Comment: 6 pages, ApJ, accepted for publicatio
Herschel observations of gamma-ray burst host galaxies: implications for the topology of the dusty interstellar medium
Long-duration gamma-ray bursts (GRBs) are indisputably related to star
formation, and their vast luminosity in gamma rays pin-points regions of star
formation independent of galaxy mass. As such, GRBs provide a unique tool for
studying star forming galaxies out to high-z independent of luminosity. Most of
our understanding of the properties of GRB hosts (GRBHs) comes from optical and
near-infrared (NIR) follow-up observations, and we therefore have relatively
little knowledge of the fraction of dust-enshrouded star formation that resides
within GRBHs. Currently ~20% of GRBs show evidence of significant amounts of
dust along the line of sight to the afterglow through the host galaxy, and
these GRBs tend to reside within redder and more massive galaxies than GRBs
with optically bright afterglows. In this paper we present Herschel
observations of five GRBHs with evidence of being dust-rich, targeted to
understand the dust attenuation properties within GRBs better. Despite the
sensitivity of our Herschel observations, only one galaxy in our sample was
detected (GRBH 070306), for which we measure a total star formation rate (SFR)
of ~100Mstar/yr, and which had a relatively high stellar mass
(log[Mstar]=10.34+0.09/-0.04). Nevertheless, when considering a larger sample
of GRBHs observed with Herschel, it is clear that stellar mass is not the only
factor contributing to a Herschel detection, and significant dust extinction
along the GRB sightline (A_{V,GRB}>1.5~mag) appears to be a considerably better
tracer of GRBHs with high dust mass. This suggests that the extinguishing dust
along the GRB line of sight lies predominantly within the host galaxy ISM, and
thus those GRBs with A_{V,GRB}>1~mag but with no host galaxy Herschel
detections are likely to have been predominantly extinguished by dust within an
intervening dense cloud.Comment: 14 pages, 7 figures. Accepted for publication in A&
Dust attenuation in 2<z<3 star-forming galaxies from deep ALMA observations of the Hubble Ultra Deep Field
17 pages, 7 figures, accepted version to be published in MNRASWe present the results of a new study of the relationship between infrared excess (IRX ≡ L IR/L UV), ultraviolet (UV) spectral slope (β) and stellar mass at redshifts 2 < z < 3, based on a deep Atacama Large Millimeter Array (ALMA) 1.3-mm continuum mosaic of the Hubble Ultra Deep Field. Excluding the most heavily obscured sources, we use a stacking analysis to show that z ≃ 2.5 star-forming galaxies in the mass range 9.25 ≤ log(M*/M ⊙) ≤ 10.75 are fully consistent with the IRX-β relation expected for a relatively grey attenuation curve, similar to the commonly adopted Calzetti law. Based on a large, mass-complete sample of 2 ≤ z ≤ 3 star-forming galaxies drawn frommultiple surveys, we proceed to derive a new empirical relationship between β and stellar mass, making it possible to predict UV attenuation (A1600) and IRX as a function of stellar mass, for any assumed attenuation law. Once again, we find that z ≃ 2.5 star-forming galaxies follow A1600-M* and IRX-M* relations consistent with a relatively grey attenuation law, and find no compelling evidence that star-forming galaxies at this epoch follow a reddening law as steep as the Small Magellanic Cloud (SMC) extinction curve. In fact, we use a simple simulation to demonstrate that previous determinations of the IRX-β relation may have been biased towards low values of IRX at red values of β, mimicking the signature expected for an SMC-like dust law. We show that this provides a plausible mechanism for reconciling apparently contradictory results in the literature and that, based on typical measurement uncertainties, stellar mass provides a cleaner prediction of UV attenuation than β. Although the situation at lower stellar masses remains uncertain, we conclude that for 2 < z < 3 star-forming galaxies with log(M*/M ⊙) ≥ 9.75, both the IRX-β and IRX-M* relations are well described by a Calzetti-like attenuation law.Peer reviewe
Multimodal Treatment With ECT for Identity Integration in a Patient With Dissociative Identity Disorder, Complex Post-traumatic Stress Disorder, and Major Depressive Disorder: A Rare Case Report
The legitimacy and etiology of Dissociative Identity Disorder (DID) remains a controversial topic within Psychiatry. The two schools of thought are the Post-Traumatic Model (PTM) and the Socio-Cognitive Model (SCM). This case highlights the validity of PTM in an individual who suffered severe and prolonged physical, psychological, and sexual abuse from 2 years old through adulthood. The reported abuse was corroborated and proven on two separate occasions via medical professionals/rape kit and the police. This resulted in the incarceration of one of her abusers. The only way for the patient to cope with the trauma she suffered was to dissociate, which resulted in the development of four full identity alters. In addition to being diagnosed with DID, the patient has been diagnosed with Major Depressive Disorder (MDD), Post-Traumatic Stress Disorder (PTSD), and chronic suicidality. Unable to manage the suicidal ideations and MDD after nearly 10 years of therapy and psychiatric medications, the patient was referred for Electroconvulsive Therapy (ECT). Upon receiving ECT weekly for 2 years, the patient reported having “lost the others.” As ECT progressed she went from having four alters to no alters and at the time of this report only being able to vaguely hear alter #4. With the integration of these alters she had access to the memories and pain that the alters had protected her from. Prior to losing the alters, her long-term memory was impaired by dissociative processes. Her long-term memory was also impaired because when one of the alters was in control of consciousness only that alter remembered what had happened during that time, unless that alter shared what had happened with one or more of the others. It is unclear if frequent ECT was the catalyst that lead to the integration of her alters however, integration finally began following prolonged ECT. This case highlights the importance of the PTM as an etiological description for DID and the importance of mental health providers further studying and researching the effects of ECT on patients with chronic MDD, PTSD, and suicidal intent, especially if these are comorbid with DID
Identification of z~>2 Herschel 500 micron sources using color-deconfusion
We present a new method to search for candidate z~>2 Herschel 500{\mu}m
sources in the GOODS-North field, using a S500{\mu}m/S24{\mu}m "color
deconfusion" technique. Potential high-z sources are selected against
low-redshift ones from their large 500{\mu}m to 24{\mu}m flux density ratios.
By effectively reducing the contribution from low-redshift populations to the
observed 500{\mu}m emission, we are able to identify counterparts to high-z
500{\mu}m sources whose 24{\mu}m fluxes are relatively faint. The recovery of
known z~4 starbursts confirms the efficiency of this approach in selecting
high-z Herschel sources. The resulting sample consists of 34 dusty star-forming
galaxies at z~>2. The inferred infrared luminosities are in the range
1.5x10^12-1.8x10^13 Lsun, corresponding to dust-obscured star formation rates
(SFRs) of ~260-3100 Msun/yr for a Salpeter IMF. Comparison with previous SCUBA
850{\mu}m-selected galaxy samples shows that our method is more efficient at
selecting high-z dusty galaxies with a median redshift of z=3.07+/-0.83 and 10
of the sources at z~>4. We find that at a fixed luminosity, the dust
temperature is ~5K cooler than that expected from the Td-LIR relation at z<1,
though different temperature selection effects should be taken into account.
The radio-detected subsample (excluding three strong AGN) follows the
far-infrared/radio correlation at lower redshifts, and no evolution with
redshift is observed out to z~5, suggesting that the far-infrared emission is
star formation dominated. The contribution of the high-z Herschel 500{\mu}m
sources to the cosmic SFR density is comparable to that of SMG populations at
z~2.5 and at least 40% of the extinction-corrected UV samples at z~4
(abridged).Comment: 33 pages in emulateapj format, 24 figures, 2 tables, accepted for
publication in the ApJ
(16) Psyche: A mesosiderite-like asteroid?
Asteroid (16) Psyche is the target of the NASA Psyche mission. It is
considered one of the few main-belt bodies that could be an exposed
proto-planetary metallic core and that would thus be related to iron
meteorites. Such an association is however challenged by both its near- and
mid-infrared spectral properties and the reported estimates of its density.
Here, we aim to refine the density of (16) Psyche to set further constraints on
its bulk composition and determine its potential meteoritic analog.
We observed (16) Psyche with ESO VLT/SPHERE/ZIMPOL as part of our large
program (ID 199.C-0074). We used the high angular resolution of these
observations to refine Psyche's three-dimensional (3D) shape model and
subsequently its density when combined with the most recent mass estimates. In
addition, we searched for potential companions around the asteroid. We derived
a bulk density of 3.99\,\,0.26\,gcm for Psyche. While such
density is incompatible at the 3-sigma level with any iron meteorites
(7.8\,gcm), it appears fully consistent with that of
stony-iron meteorites such as mesosiderites (density
4.25\,cm). In addition, we found no satellite in our images
and set an upper limit on the diameter of any non-detected satellite of
1460\,\,200}\,m at 150\,km from Psyche (0.2\%\,\,R, the
Hill radius) and 800\,\,200\,m at 2,000\,km (3\%\,\,).
Considering that the visible and near-infrared spectral properties of
mesosiderites are similar to those of Psyche, there is merit to a
long-published initial hypothesis that Psyche could be a plausible candidate
parent body for mesosiderites.Comment: 16 page
Herschel-ATLAS : The spatial clustering of low and high redshift submillimetre galaxies
We present measurements of the angular correlation function of sub-millimeter (sub-mm) galaxies (SMGs) identified in four out of the five fields of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) − GAMA-9h, GAMA-12h, GAMA-15h and NGP − with flux densities S250μm>30 mJy at 250 μm. We show that galaxies selected at this wavelength trace the underlying matter distribution differently at low and high redshifts. We study the evolution of the clustering finding that at low redshifts sub-mm galaxies exhibit clustering strengths of r0 ∼ 2 − 3 h−1Mpc, below z < 0.3. At high redshifts, on the other hand, we find that sub-mm galaxies are more strongly clustered with correlation lengths r0 = 8.1 ± 0.5, 8.8 ± 0.8 and 13.9 ± 3.9 h−1Mpc at z = 1 − 2, 2 − 3 and 3 − 5, respectively. We show that sub-mm galaxies across the redshift range 1 < z < 5, typically reside in dark-matter halos of mass of the order of ∼ 1012.5 − 1013.0h−1M⊙ and are consistent with being the progenitors of local massive elliptical galaxies that we see in the local Universe
KOMBINIRANO DJELOVANJE BITURATA I EKSTRAKTA YUCCA SCHIDIGERI NA GASTROINTESTINALNI SUSTAV SVINJA OKO ODBIJANJA
After the banning of antibiotics as growth promoters, animal production in the EU faced the problem of increased post-weaning disorders, and several solutions were proposed (acidifiers, probiotics, herb extracts, enzyme cocktails, etc.). Short chain fatty acids (SCFA) are the main end product of bacterial fermentation in the hind gut in monogastric animals and can be used as energy supply for the epithelial cells of gut mucosa. Thus the aim of the study was to test the usefulness of novel microencapsulated sodium butyrate and Yucca Schidigera extract (encourages friendly bacteria growth, reduces ammonia) preparation on pig performance and small intestine development in the critical weaning period. Microencapsulation helps to avoid stomach degradation and provides better distribution of the compounds along the small intestine. Suckling piglets, 14-day old, were divided into 2 groups, control and with butyrate addition. Control pigs received a standard feed supplemented with a microencapsulated acidifier (0.3%). Butyrate pigs received the same feed and acidifier, as controls, supplemented with butyrate/yucca preparation (0.3%). At days 28 (weaning), 35 and 56 of life, 6 pigs from each group were killed and the gastrointestinal tract was harvested and measured. The initial body weight (14 d) of pigs from the control group was higher than that of the experimental, but at day 56 it did not differ significantly (P=0.48). The relative stomach and pancreas weights in the experimental group showed a tendency toward higher values in all time points, and the small intestine relative weight in day 35 was higher as compared to the controls. The growth rate of the pigs at day 35 decreased significantly in the control (P=0.007), but did not in the experimental (P=0.058) group compared to day 31. Measurements of the small intestine sections revealed increased mucosa thickness in butyrate treated pigs. This was due to both villi and crypt enlargement. In conclusion, our results demonstrated the effectiveness sodium butyrate and Yucca Shidigera extract in the prevention of weaning problems in pigs, however further research on the novel preparation is needed.Nakon zabrane antibiotika kao promotora rasta, proizvodnja životinja u EU suočila se sa sve više poremećaja nakon odbijanja pa je predloženo nekoliko rješenja (acidifikatori, probiotici, biljni ekstrakti, kokteli enzima, itd.). Kratkolančane masne kiseline glavni su krajnji proizvod bakterijske fermentacije u stražnjem crijevu u monogastričnih životinja pa se mogu upotrijebiti za snabdijevanje energijom epitelnih stanica crijevne sluznice /mukoze. Stoga je cilj ovog rada bio testirati korisnost novog natrijevog biturata u mikrokapsuli i pripravka ekstrakta Yucca Schidigera (potiče rast dobročudnih bakterija, smanjuje amonijak) na performansu svinja i razvoj tankog crijeva u kritičnom razdoblju odbijanja. Mikrokapsule pomažu da se izbjegne oštećenje želuca i pruža bolju razdiobu spojeva duž tankog crijeva. Praščići na sisi, u dobi od 14 dana, bili su podijeljeni u dvije skupine, kontrolnu i skupinu s dodavanjem biturata. Kontrolni praščići dobivali su standardnu hranu s dodatkom acidifikatora/zakiseljivača u mikrokapsuli (0.03%). Praščići na bituratima dobivali su istu hranu i acidifikator/zakiseljivač s dodatkom biturata/yucca pripravka (0.03%). U dobi od 28 (odbijanje), 35 i 56 dana žrtvovano je 6 svinja iz svake skupine te je pregledan i izmjeren gastrointestinalni sustav. Početna tjelesna masa (14. dan) svinja iz kontrolne skupine bila je veća od mase svinja pokusne skupine ali 56. dan nije se značajno razlikovala (P=0.48). Relativne mase želuca i gušterače u pokusnoj skupini pokazale su tendenciju viših vrijednosti u svim razdobljima, a relativna masa tankog crijeva 35. dana bila je viša u usporedbi s kontrolnom skupinom. Stopa rasta svinja 35. dana znatno se smanjila u kontrolnoj skupini (P=0.007) ali ne u kontrolnoj skupini (P=0.058) u usporedbi s 31. danom. Mjere tankog crijeva pokazale su povećanu debljinu sluznice u svinja tretiranih bituratom. To se pripisuje povećanju dlačica i udubina (villi i crypt). U zaključku, naši su rezultati pokazali djelotvornost natrijevog biturata i ekstrakta Yucca Schidigeri u prevenciji problema odbijanja u svinja, međutim, potrebna su dalja istraživanja novih pripravaka
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