scholarly journals ALMA observations of envelopes around first hydrostatic core candidates

2020 ◽  
Vol 499 (3) ◽  
pp. 4394-4417
Author(s):  
María José Maureira ◽  
Héctor G Arce ◽  
Michael M Dunham ◽  
Diego Mardones ◽  
Andrés E Guzmán ◽  
...  
Keyword(s):  
High Density ◽  
No Emission ◽  
Molecular Line ◽  
Continuum Source ◽  
Evolutionary State ◽  
Bona Fide ◽  
Rule Out

ABSTRACT We present ALMA 3 mm molecular line and continuum observations with a resolution of ∼3.5 arcsec towards five first hydrostatic core (FHSC) candidates (L1451-mm, Per-bolo 58, Per-bolo 45, L1448-IRS2E, and Cha-MMS1). Our goal is to characterize their envelopes and identify the most promising sources that could be bona fide FHSCs. We identify two candidates that are consistent with an extremely young evolutionary state (L1451-mm and Cha-MMS1), with L1451-mm being the most promising FHSC candidate. Although our envelope observations cannot rule out Cha-MMS1 as an FHSC yet, the properties of its CO outflow and SED published in recent studies are in better agreement with the predictions for a young protostar. For the remaining three sources, our observations favour a pre-stellar nature for Per-bolo 45 and rule out the rest as FHSC candidates. Per-bolo 58 is fully consistent with being a Class 0, while L1448 IRS2E shows no emission of high-density tracers (NH2D and N2H+) at the location of the previously identified compact continuum source, which is also undetected in our observations. Thus, we argue that there is no embedded source at the presumptive location of the FHSC candidate L1448 IRS2E. We propose instead that what was thought to be emission from the presumed L1448 IRS2E outflow corresponds to outflow emission from a nearby Class 0 system, deflected by the dense ambient material. We compare the properties of the FHSC candidates studied in this work and the literature, which shows that L1451-mm appears as possibly the youngest source with a confirmed outflow.

scholarly journals The Circumstellar Environment of LkHα 234

1987 ◽  
Vol 115 ◽  
pp. 368-368
Author(s):  
B. A. Wilking ◽  
L. G. Mundy ◽  
R. D. Schwartz
Keyword(s):  
High Resolution ◽  
Millimeter Wave ◽  
Spectral Dependence ◽  
Large Scale ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Owens Valley ◽  
Molecular Line ◽  
Continuum Source ◽  
Circumstellar Environment

We present high resolution (HPBW = 5 arcsec) continuum and molecular-line observations of the circumstellar environment of the emission-line star LkHα 234 made with the Owens Valley Millimeter-Wave Interferometer. These 98 GHz observations have revealed an unresolved continuum source coincident with the star and a 10 000 by 17000 A.U. ridge of enhanced CS(2-1) emission which peaks ∼ 4″ east of the star. The resulting spectral dependence for the radio continuum emission of ν1.5 is most easily interpreted as arising from a partially ionized stellar wind. Attempts are made to describe the properties of the CS emission in terms of a rotating molecular disk which would link LkHα 234 with large scale mass loss activity in the cloud. However, it appears most likely that the CS emission is arising from a dense (n(H2) ∼ 106 cm −3) condensation of gas adjacent to, but not dynamically associated with, the star.

scholarly journals G133.50+9.01: a likely cloud–cloud collision complex triggering the formation of filaments, cores, and a stellar cluster

2020 ◽  
Vol 499 (3) ◽  
pp. 3620-3629
Author(s):  
Namitha Issac ◽  
Anandmayee Tej ◽  
Tie Liu ◽  
Yuefang Wu
Keyword(s):  
Cluster Formation ◽  
Observational Evidence ◽  
Young Stellar Objects ◽  
Molecular Line ◽  
Stellar Objects ◽  
Stellar Cluster ◽  
Dense Cores ◽  
Bolometer Array ◽  
Bona Fide ◽  
Common User

ABSTRACT We present compelling observational evidence of G133.50+9.01 being a bona fide cloud–cloud collision candidate with signatures of induced filament, core, and cluster formation. The CO molecular line observations reveal that the G133.50+9.01 complex is made of two colliding molecular clouds with systemic velocities, $\rm -16.9$ and $\rm -14.1\, km\, s^{-1}$. The intersection of the clouds is characterized by broad bridging features characteristic of collision. The morphology of the shocked layer at the interaction front resembles an arc-like structure with enhanced excitation temperature and H2 column density. A complex network of filaments is detected in the Submillimeter Common-User Bolometer Array 2 850 $\rm \mu m$ image with 14 embedded dense cores, all well correlated spatially with the shocked layer. A stellar cluster revealed through an overdensity of identified Classes I and II young stellar objects is found located along the arc in the intersection region corroborating with a likely collision induced origin.

scholarly journals Is Too Much of a Good Thing a Good Thing? Extremely high high-density lipoprotein cholesterol with Coronary artery disease, Case report.

2021 ◽  
Author(s):  
Khalid Sawalha ◽  
Gilbert-Roy Kamoga
Keyword(s):  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
High Density ◽  
Good Thing ◽  
High Density Lipoprotein Level ◽  
Lipoprotein Level ◽  
Disease Case ◽  
High High Density Lipoprotein ◽  
Artery Disease ◽  
Rule Out

A 52-year-old female was admitted to rule out an acute coronary syndrome.Her Troponin, ECG, MPS were negative. Further testing she was found to have extremely high high-density lipoprotein level of 218 mg/dl.Due to the persistent nature of the chest pain, LHC was done with 50% stenosis of RCA.

scholarly journals Chicken yolk contains bona fide high density lipoprotein particles.

1995 ◽  
Vol 36 (3) ◽  
pp. 601-610
Author(s):  
P M Vieira ◽  
A V Vieira ◽  
E J Sanders ◽  
E Steyrer ◽  
J Nimpf ◽  
...  
Keyword(s):  
High Density Lipoprotein ◽  
Density Lipoprotein ◽  
High Density ◽  
Lipoprotein Particles ◽  
Bona Fide

Planar defects in ordered (Ga,In)P

1988 ◽  
Vol 46 ◽  
pp. 902-903
Author(s):  
S. McKernan ◽  
C. B. Carter ◽  
D. Bour ◽  
J. R. Shealy
Keyword(s):  
Electron Diffraction ◽  
Vapor Phase ◽  
Growth Direction ◽  
High Density ◽  
Ordered Structure ◽  
Planar Defects ◽  
Diffraction Patterns ◽  
Ternary Semiconductors ◽  
Anion Species ◽  
Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

1995 ◽  
Vol 53 ◽  
pp. 512-513
Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf
Keyword(s):  
Sample Preparation ◽  
Milling Time ◽  
High Density ◽  
Low Density ◽  
Ion Milling ◽  
High Quality ◽  
Variable Angle ◽  
Major Disadvantage ◽  
Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

Using the scanning electron microscope for failure analysis of high density magnetic media

1987 ◽  
Vol 45 ◽  
pp. 392-393
Author(s):  
Evelyn R. Ackerman ◽  
Gary D. Burnett
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Failure Analysis ◽  
High Density ◽  
Magnetic Media ◽  
Specific Data ◽  
Retrieval Systems ◽  
Operating Environments ◽  
The Media ◽  
Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

A rapid method for the direct identification of paramyxovirus in canine CSF by ultracentrifugation and negative staining as a rule out for distemper

1990 ◽  
Vol 48 (3) ◽  
pp. 594-595
Author(s):  
W.L. Steffens ◽  
M.B. Ard ◽  
C.E. Greene ◽  
A. Jaggy
Keyword(s):  
Subacute Sclerosing Panencephalitis ◽  
Clinical Signs ◽  
Viral Disease ◽  
Etiologic Agent ◽  
Mucosal Inflammation ◽  
Worldwide Distribution ◽  
Negative Stain ◽  
Viral Particles ◽  
Systemic Manifestations ◽  
Rule Out

Canine distemper is a multisystemic contagious viral disease having a worldwide distribution, a high mortality rate, and significant central neurologic system (CNS) complications. In its systemic manifestations, it is often presumptively diagnosed on the basis of clinical signs and history. Few definitive antemortem diagnostic tests exist, and most are limited to the detection of viral antigen by immunofluorescence techniques on tissues or cytologic specimens or high immunoglobulin levels in CSF (cerebrospinal fluid). Diagnosis of CNS distemper is often unreliable due to the relatively low cell count in CSF (<50 cells/μl) and the binding of blocking immunoglobulins in CSF to cell surfaces. A more reliable and definitive test might be possible utilizing direct morphologic detection of the etiologic agent. Distemper is the canine equivalent of human measles, in that both involve a closely related member of the Paramyxoviridae, both produce mucosal inflammation, and may produce CNS complications. In humans, diagnosis of measles-induced subacute sclerosing panencephalitis is through negative stain identification of whole or incomplete viral particles in patient CSF.

Impairment Questions and Answers

1999 ◽  
Vol 4 (4) ◽  
pp. 4-4
Keyword(s):  
Symptom Validity ◽  
Validity Testing ◽  
Symptom Validity Testing ◽  
Negative Results ◽  
Tunnel Vision ◽  
Questions And Answers ◽  
Blurry Vision ◽  
Fatigue Evaluation ◽  
Choice Testing ◽  
Rule Out

Abstract Symptom validity testing, also known as forced-choice testing, is a way to assess the validity of sensory and memory deficits, including tactile anesthesias, paresthesias, blindness, color blindness, tunnel vision, blurry vision, and deafness—the common feature of which is a claimed inability to perceive or remember a sensory signal. Symptom validity testing comprises two elements: A specific ability is assessed by presenting a large number of items in a multiple-choice format, and then the examinee's performance is compared with the statistical likelihood of success based on chance alone. Scoring below a norm can be explained in many different ways (eg, fatigue, evaluation anxiety, limited intelligence, and so on), but scoring below the probabilities of chance alone most likely indicates deliberate deception. The positive predictive value of the symptom validity technique likely is quite high because there is no alternative explanation to deliberate distortion when performance is below the probability of chance. The sensitivity of this technique is not likely to be good because, as with a thermometer, positive findings indicate that a problem is present, but negative results do not rule out a problem. Although a compelling conclusion is that the examinee who scores below probabilities is deliberately motivated to perform poorly, malingering must be concluded from the total clinical context.

Case Exercise: Toxic Exposure-Related Illness: Causation, Diagnosis, and Permanent Impairment

2007 ◽  
Vol 12 (2) ◽  
pp. 4-8
Author(s):  
Frederick Fung
Keyword(s):  
Concentration Level ◽  
Treatment Plan ◽  
Toxic Exposure ◽  
Dose Response Relationship ◽  
Specialty Board ◽  
History Of ◽  
Subjective Complaints ◽  
Based Medicine ◽  
Illness Causation ◽  
Rule Out

Abstract A diagnosis of toxic-related injury/illness requires a consideration of the illness related to the toxic exposure, including diagnosis, causation, and permanent impairment; these are best performed by a physician who is certified by a specialty board certified by the American Board of Preventive Medicine. The patient must have a history of symptoms consistent with the exposure and disease at issue. In order to diagnose the presence of a specific disease, the examiner must find subjective complaints that are consistent with the objective findings, and both the subjective complaints and objective findings must be consistent with the disease that is postulated. Exposure to a specific potentially causative agent at a defined concentration level must be documented and must be sufficient to induce a particular pathology in order to establish a diagnosis. Differential diagnoses must be entertained in order to rule out other potential causes, including psychological etiology. Furthermore, the identified exposure at the defined concentration level must be capable of causing the diagnosis being postulated before the examiner can conclude that there has been a cause-and-effect relationship between the exposure and the disease (dose-response relationship). The evaluator's opinion should make biological and epidemiological sense. The treatment plan and prognosis should be consistent with evidence-based medicine, and the rating of impairment must be based on objective findings in involved systems.

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