Objective
As in other health sciences, a career in dentistry is associated with numerous stressors in practitioners. The main objective of this research was to examine the prevalence of emotional ...exhaustion, burnout, and perceived stress among dental students in Mexico.
Methods
A cross-sectional study was conducted among 73 dental students attending a private university in Northern Mexico. Three scales were administered to students to identify emotional exhaustion, burnout, and perceived stress, and parametric data analysis was performed.
Results
Among participants (mean age 19.7 years), the proportion with emotional exhaustion, perceived high stress, and burnout was 52.0%, 42.3%, and 17.8%, respectively. All students with perceived stress also had burnout.
Conclusions
We found that emotional exhaustion and perceived stress are experienced by a large proportion of dentistry students enrolled in the third semester at this private university in Northern Mexico. The proportions were independent of age and sex.
Aims.
The complexity of star formation at the physical scale of molecular clouds is not yet fully understood. We investigate the mechanisms regulating the formation of stars in different environments ...within nearby star-forming galaxies from the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) sample.
Methods.
Integral field spectroscopic data and radio-interferometric observations of 18 galaxies were combined to explore the existence of the resolved star formation main sequence (Σ
stellar
versus Σ
SFR
), resolved Kennicutt–Schmidt relation (Σ
mol. gas
versus Σ
SFR
), and resolved molecular gas main sequence (Σ
stellar
versus Σ
mol. gas
), and we derived their slope and scatter at spatial resolutions from 100 pc to 1 kpc (under various assumptions).
Results.
All three relations were recovered at the highest spatial resolution (100 pc). Furthermore, significant variations in these scaling relations were observed across different galactic environments. The exclusion of non-detections has a systematic impact on the inferred slope as a function of the spatial scale. Finally, the scatter of the Σ
mol. gas + stellar
versus Σ
SFR
correlation is smaller than that of the resolved star formation main sequence, but higher than that found for the resolved Kennicutt–Schmidt relation.
Conclusions.
The resolved molecular gas main sequence has the tightest relation at a spatial scale of 100 pc (scatter of 0.34 dex), followed by the resolved Kennicutt–Schmidt relation (0.41 dex) and then the resolved star formation main sequence (0.51 dex). This is consistent with expectations from the timescales involved in the evolutionary cycle of molecular clouds. Surprisingly, the resolved Kennicutt–Schmidt relation shows the least variation across galaxies and environments, suggesting a tight link between molecular gas and subsequent star formation. The scatter of the three relations decreases at lower spatial resolutions, with the resolved Kennicutt–Schmidt relation being the tightest (0.27 dex) at a spatial scale of 1 kpc. Variation in the slope of the resolved star formation main sequence among galaxies is partially due to different detection fractions of Σ
SFR
with respect to Σ
stellar
.
A procedure to select the controlling factors connected to the slope instability has been defined. It allowed us to assess the landslide susceptibility in the Rio Beiro basin (about 10 km2) over the ...northeastern area of the city of Granada (Spain). Field and remote (Google EarthTM) recognition techniques allowed us to generate a landslide inventory consisting in 127 phenomena. To discriminate between stable and unstable conditions, a diagnostic area had been chosen as the one limited to the crown and the toe of the scarp of the landslide. 15 controlling or determining factors have been defined considering topographic, geologic, geomorphologic and pedologic available data. Univariate tests, using both association coefficients and validation results of single-variable susceptibility models, allowed us to select the best predictors, which were combined for the unique conditions analysis. For each of the five recognised landslide typologies, susceptibility maps for the best models were prepared. In order to verify both the goodness of fit and the prediction skill of the susceptibility models, two different validation procedures were applied and compared. Both procedures are based on a random partition of the landslide archive for producing a test and a training subset. The first method is based on the analysis of the shape of the success and prediction rate curves, which are quantitatively analysed exploiting two morphometric indexes. The second method is based on the analysis of the degree of fit, by considering the relative error between the intersected target landslides by each of the different susceptibility classes in which the study area was partitioned. Both the validation procedures confirmed a very good predictive performance of the susceptibility models and of the actual procedure followed to select the controlling factors.
We present 3.7 arcsec (∼0.05 pc) resolution 3.2 mm dust continuum observations from the Institut de Radioastronomie Millimétrique Plateau de Bure Interferometer, with the aim of studying the ...structure and fragmentation of the filamentary infrared dark cloud (IRDC) G035.39–00.33. The continuum emission is segmented into a series of 13 quasi-regularly spaced (λobs ∼ 0.18 pc) cores, following the major axis of the IRDC. We compare the spatial distribution of the cores with that predicted by theoretical work describing the fragmentation of hydrodynamic fluid cylinders, finding a significant (a factor of ≳ 8) discrepancy between the two. Our observations are consistent with the picture emerging from kinematic studies of molecular clouds suggesting that the cores are harboured within a complex network of independent sub-filaments. This result emphasizes the importance of considering the underlying physical structure, and potentially, dynamically important magnetic fields, in any fragmentation analysis. The identified cores exhibit a range in (peak) beam-averaged column density (3.6 × 1023 cm−2 < N
H, c < 8.0 × 1023 cm−2), mass (8.1 M⊙ < M
c < 26.1 M⊙), and number density (6.1 × 105 cm−3 < n
H, c, eq < 14.7 × 105 cm−3). Two of these cores, dark in the mid-infrared, centrally concentrated, monolithic (with no traceable substructure at our PdBI resolution), and with estimated masses of the order ∼20–25 M⊙, are good candidates for the progenitors of intermediate-to-high-mass stars. Virial parameters span a range 0.2 < αvir < 1.3. Without additional support, possibly from dynamically important magnetic fields with strengths of the order of 230 μG < B < 670 μG, the cores are susceptible to gravitational collapse. These results may imply a multilayered fragmentation process, which incorporates the formation of sub-filaments, embedded cores, and the possibility of further fragmentation.
Dusty star-forming galaxies at high redshift (1 < z < 3) represent the most intense star-forming regions in the universe. Key aspects to these processes are the gas heating and cooling mechanisms, ...and although it is well known that these galaxies are gas-rich, little is known about the gas excitation conditions. Only a few detailed radiative transfer studies have been carried out owing to a lack of multiple line detections per galaxy. Here we examine these processes in a sample of 24 strongly lensed star-forming galaxies identified by the Planck satellite (LPs) at z ∼ 1.1-3.5. We analyze 162 CO rotational transitions (ranging from Jup = 1 to 12) and 37 atomic carbon fine-structure lines (C i) in order to characterize the physical conditions of the gas in the sample of LPs. We simultaneously fit the CO and C i lines and the dust continuum emission, using two different non-LTE, radiative transfer models. The first model represents a two-component gas density, while the second assumes a turbulence-driven lognormal gas density distribution. These LPs are among the most gas-rich, IR-luminous galaxies ever observed ( L L IR ( 8 − 1000 m ) ∼ 10 13 − 14.6 L ; 〈 LMISM 〉 = (2.7 1.2) × 1012 M , with L ∼ 10-30 the average lens magnification factor). Our results suggest that the turbulent interstellar medium present in the LPs can be well characterized by a high turbulent velocity dispersion ( 〈 ΔVturb 〉 ∼ 100 km s−1) and ratios of gas kinetic temperature to dust temperature 〈 Tkin/Td 〉 ∼ 2.5, sustained on scales larger than a few kiloparsecs. We speculate that the average surface density of the molecular gas mass and IR luminosity, M ISM ∼ 103-4 M pc−2 and L IR ∼ 1011-12 L kpc−2, arise from both stellar mechanical feedback and a steady momentum injection from the accretion of intergalactic gas.
We investigate the relative impact of topological, geometric, and hydraulic heterogeneity on transport processes in three‐dimensional fracture networks. Focusing on the two largest scales of ...heterogeneity in these systems, individual fracture and network structure, we compare transport through analogous structured and disordered three‐dimensional fracture networks with varying degrees of hydraulic heterogeneity. For the moderate levels of hydraulic heterogeneity we consider, network structure is the dominant control of transport through the networks. Less dispersion, both longitudinal and transverse, is observed in structured networks than in disordered networks, due in part to the higher connectivity in the former, independent of the level of hydraulic heterogeneity. However, increases in dispersion with higher hydraulic heterogeneity are larger in the disordered networks than in the structured networks, thereby indicating that the interplay between structural and hydraulic heterogeneity is nonlinear. We propose a measure of disorder in fracture networks by computing the Shannon entropy of the spectrum of the Laplacian of a weighted graph representation of the networks, where the weights are given by a combination of topological, geometric, and hydraulic properties. This metric, as a relative indicator by comparison between two networks, is a first approach to the dispersion potential and “mixing capacity” of a fracture network.
Key Points
For moderate levels of hydraulic heterogeneity, fracture network structure is the principal control of transport times and dispersion
The influence of the interplay between structural and hydraulic heterogeneity is nonlinear
As hydraulic heterogeneity increased, both longitudinal and transverse dispersion also increased
Infrared dark clouds (IRDCs) are unique laboratories to study the initial conditions of high-mass star and star cluster formation. We present high-sensitivity and high-angular-resolution Institut de ...Radioastronomie Millim...trique (IRAM) Plateau de Bure Interferometer observations of N^sub 2^H+ (1-0) towards IRDC G035.39-00.33. It is found that G035.39...00.33 is a highly complex environment, consisting of several mildly supersonic filaments (σ^sub NT^/c^sub s^ ~ 1.5), separated in velocity by <1 km s^sup -1^. Where multiple spectral components are evident, moment analysis overestimates the non-thermal contribution to the line-width by a factor of ~2. Large-scale velocity gradients evident in previous single-dish maps may be explained by the presence of substructure now evident in the interferometric maps. Whilst global velocity gradients are small (<0.7 km s^sup -1^ pc^sup -1^), there is evidence for dynamic processes on local scales (~1.5-2.5 km s^sup -1^ pc^sup -1^). Systematic trends in velocity gradient are observed towards several continuum peaks. This suggests that the kinematics are influenced by dense (and in some cases, starless) cores. These trends are interpreted as either infalling material, with accretion rates ~(7 ± 4) x 10^sup -5^ M... yr^sup -1^, or expanding shells with momentum ~24 ± 12 M... km s^sup -1^. These observations highlight the importance of high-sensitivity and high-spectral-resolution data in disentangling the complex kinematic and physical structure of massive star-forming regions. (ProQuest: ... denotes formulae/symbols omitted.)
To compare medium- and long-term postoperative surgical results, especially the adjacent syndrome rate, adverse event rate, and reoperation rate, of patients operated on with cervical arthroplasty or ...anterior cervical arthrodesis in published randomized clinical trials (RCTs), at one cervical level.
Systematic review and meta-analysis. Thirteen RCTs were selected. The clinical, radiological and surgical results were analyzed, taking the adjacent syndrome rate and the reoperation rate as the primary objective of the study.
Two thousand nine hundred and sixty three patients were analyzed. The cervical arthroplasty group showed a lower rate of superior adjacent syndrome (P<0.001), lower reoperation rate (P<0.001), less radicular pain (P=0.002), and a better score of neck disability index (P=0.02) and SF-36 physical component (P=0.01). No significant differences were found in the lower adjacent syndrome rate, adverse event rate, neck pain scale, or SF-36 mental component. A range of motion of 7.91° was also found at final follow-up, and a heterotopic ossification rate of 9.67% in patients with cervical arthroplasty.
In the medium and long-term follow-up, cervical arthroplasty showed a lower rate of superior adjacent syndrome and a lower rate of reoperation. No statistically significant differences were found in the rate of inferior adjacent syndrome or in the rate of adverse events.
Comparar a mediano y a largo plazo los resultados quirúrgicos postoperatorios, sobre todo la tasa del síndrome adyacente, la tasa de eventos adversos y la tasa de reoperación, de los pacientes operados con artroplastia cervical o artrodesis cervical anterior en los ensayos clínicos aleatorizados (ECA) publicados de un nivel cervical.
Revisión sistemática y metaanálisis. Se seleccionaron 13 ECA. Se analizaron los resultados clínicos, radiológicos y quirúrgicos, tomando como variables primarias la tasa del síndrome adyacente, la tasa de eventos adversos y la tasa de reoperación.
Fueron 2.963 los pacientes analizados. El grupo de artroplastia cervical mostró una menor tasa de síndrome adyacente superior (p<0,001), una menor tasa de reoperación (p<0,001), un menor dolor radicular (p=0,002) y una mejor puntuación en el índice de discapacidad cervical (p=0,02) y en el componente físico SF-36 (p=0,01). No se encontraron diferencias significativas en la tasa del síndrome adyacente inferior, en la tasa de eventos adversos, en el dolor cervical ni en el componente mental SF-36. En la artroplastia cervical se halló un rango de movilidad medio de 7,91 grados en el seguimiento final y una tasa de osificación heterotópica del 9,67%.
En el seguimiento a mediano y a largo plazo, la artroplastia cervical mostró una menor tasa de síndrome adyacente superior y una menor tasa de reintervención. No se hallaron diferencias estadísticamente significativas en la tasa del síndrome adyacente inferior ni en la tasa de eventos adversos.
We present new H
I
observations of the nearby massive spiral galaxy M 83 taken with the JVLA at 21″ angular resolution (≈500 pc) of an extended (∼1.5 deg
2
) ten-point mosaic combined with GBT ...single-dish data. We study the super-extended H
I
disk of M 83 (∼50 kpc in radius), in particular disk kinematics, rotation, and the turbulent nature of the atomic interstellar medium. We define distinct regions in the outer disk (
r
gal
> central optical disk), including a ring, a southern area, a southern arm and a northern arm. We examine H
I
gas surface density, velocity dispersion, and noncircular motions in the outskirts, which we compare to the inner optical disk. We find an increase of velocity dispersion (
σ
v
) toward the pronounced H
I
ring, indicative of more turbulent H
I
gas. Additionally, we report over a large galactocentric radius range (until
r
gal
∼ 50 kpc) where
σ
v
is slightly larger than thermal component (i.e., > 8 km s
−1
). We find that a higher star-formation rate (as traced by far UV emission) is not necessarily always associated with a higher H
I
velocity dispersion, suggesting that radial transport could be a dominant driver for the enhanced velocity dispersion. Furthermore, we find a possible branch that connects the extended H
I
disk to the dwarf irregular galaxy UGCA 365 and that deviates from the general direction of the northern arm. Lastly, we compare mass flow rate profiles (based on 2D and 3D tilted ring models) and find evidence for outflowing gas at
r
gal
∼ 2 kpc, inflowing gas at
r
gal
∼ 5.5 kpc, and outflowing gas at
r
gal
∼ 14 kpc. We caution that mass flow rates are highly sensitive to the assumed kinematic disk parameters, in particular to inclination.
PDF
![[Translated article] Less s...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1888-4415/small "[Translated article] Less superior adjacent syndrome and lower reoperation rate. Medium- and long-term results of cervical arthroplasty versus anterior cervical arthrodesis: Systematic review and meta-analysis of randomized clinical trials")