971 research outputs found
Short and Long-term Changes in the Fish Assemblages of Bayou Lacombe, Louisiana
Over the past thirty-five years, anthropogenic disturbances around Bayou Lacombe have altered its fish assemblage. In 2005, the impact of Hurricane Katrina on southeast Louisiana presented me with a unique opportunity to explore the effects of a catastrophic storm on the Bayou. I explored the effects of natural and human disturbances on the Bayou\u27s fish assemblage by electrofishing six historically sampled stations. My research goals were to determine: 1) which Bayou Lacombe fish assemblages were most resilient to the multiple effects of Hurricane Katrina, 2) if there were significant differences in the Bayou\u27s fish assemblages over the past 35 years based on historical fish assemblage data, and 3) what are the drivers of fish assemblage change in Bayou Lacombe. I found significant differences in upstream fish assemblages before and after Hurricane Katrina in the Bayou. I also documented the disappearance of nearly all cyprinid species over the past 35 years
Short and Long-term Changes in the Fish Assemblages of Bayou Lacombe, Louisiana
Over the past thirty-five years, anthropogenic disturbances around Bayou Lacombe have altered its fish assemblage. In 2005, the impact of Hurricane Katrina on southeast Louisiana presented me with a unique opportunity to explore the effects of a catastrophic storm on the Bayou. I explored the effects of natural and human disturbances on the Bayou\u27s fish assemblage by electrofishing six historically sampled stations. My research goals were to determine: 1) which Bayou Lacombe fish assemblages were most resilient to the multiple effects of Hurricane Katrina, 2) if there were significant differences in the Bayou\u27s fish assemblages over the past 35 years based on historical fish assemblage data, and 3) what are the drivers of fish assemblage change in Bayou Lacombe. I found significant differences in upstream fish assemblages before and after Hurricane Katrina in the Bayou. I also documented the disappearance of nearly all cyprinid species over the past 35 years
Surfaces with prescribed Weingarten-Operator
We investigate pairs of surfaces in Euclidean 3-space with the same Weingarten operator in case that one surface is given as surface of revolution. Our local and global results complement global results on ovaloids of revolution from [S-V-W-W]
A contemporary assessment of devices for Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA): resource-specific options per level of care
Purpose: Use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) as adjunct for temporary hemorrhage control in patients with exsanguinating torso hemorrhage is increasing. Characteristics of aortic occlusion balloons (AOB) are diverse and evolving as efforts are made to improve the technology. It is important to select a device that fits the requirements of the medical situation to minimize the risk of failure and complications. The aim of this study is to appraise guidance in the choice of an AOB in a specific situation. Methods: We assessed 29 AOB for differences and outline possible advantages and disadvantages of each. Bending stiffness was measured with a three-point bending device. Results: Diameter of the AOB ranged from 6 (ER-REBOA™) to 10 (Coda®-46) French. However, some need large-bore access sheaths up to 22 French (Fogarty®-45 and LeMaitre®-45) or even insertion via cut-down (Equalizer™-40). Bending stiffness varied from 0.08 N/mm (± 0.008 SD; Coda®-32) to 0.72 N/mm (± 0.024 SD; Russian prototype). Rescue Balloon™ showed kinking of the shaft at low bending pressures. The only non-compliant AOB is REBOA Balloon®. ER-REBOA™, Fogarty®, LeMaitre®, REBOA Balloon®, and Rescue Balloon™ are provided with external length marks to assist blind positioning. Conclusion: In resource-limited settings, a guidewire- and fluoroscopy-free, rather stiff device, such as ER-REBOA™, Fogarty®, and LeMaitre®, is warranted. Of these devices, ER-REBOA™ is the only catheter compatible with seven French sheaths and specifically designed for emergency hemorrhage control. Of the over-the-wire devices, Q50® has several features that facilitate use and reduce the risk of malplacement or vessel damage
Presupernova Evolution of Differentially Rotating Massive Stars Including Magnetic Fields
As a massive star evolves through multiple stages of nuclear burning on its
way to becoming a supernova, a complex, differentially rotating structure is
set up. Angular momentum is transported by a variety of classic instabilities,
and also by magnetic torques from fields generated by the differential
rotation. We present the first stellar evolution calculations to follow the
evolution of rotating massive stars including, at least approximately, all
these effects, magnetic and non-magnetic, from the zero-age main sequence until
the onset of iron-core collapse. The evolution and action of the magnetic
fields is as described by Spruit 2002 and a range of uncertain parameters is
explored. In general, we find that magnetic torques decrease the final rotation
rate of the collapsing iron core by about a factor of 30 to 50 when compared
with the non-magnetic counterparts. Angular momentum in that part of the
presupernova star destined to become a neutron star is an increasing function
of main sequence mass. That is, pulsars derived from more massive stars will
rotate faster and rotation will play a more dominant role in the star's
explosion. The final angular momentum of the core is determined - to within a
factor of two - by the time the star ignites carbon burning. For the lighter
stars studied, around 15 solar masses, we predict pulsar periods at birth near
15 ms, though a factor of two range is easily tolerated by the uncertainties.
Several mechanisms for additional braking in a young neutron star, especially
by fall back, are also explored.Comment: 32 pages, 3 figures (8 eps files), submitted to Ap
A New Formation Channel for Double Neutron Stars Without Recycling: Implications for Gravitational Wave Detection
We report on a new evolutionary path leading to the formation of close double
neutron stars (NS), with the unique characteristic that none of the two NS ever
had the chance to be recycled by accretion. The existence of this channel stems
from the evolution of helium-rich stars (cores of massive NS progenitors),
which has been neglected in most previous studies of double compact object
formation. We find that these non-recycled NS-NS binaries are formed from bare
carbon-oxygen cores in tight orbits, with formation rates comparable to or
maybe even higher than those of recycled NS-NS binaries. On the other hand,
their detection probability as binary pulsars is greatly reduced (by about
1000) relative to recycled pulsars, because of their short lifetimes. We
conclude that, in the context of gravitational-wave detection of NS-NS inspiral
events, this new type of binaries calls for an increase of the rate estimates
derived from the observed NS-NS with recycled pulsars, typically by factors of
1.5-3 or even higher.Comment: Accepted for publication in ApJ Letters; 5 pages, 1 figure, 2 tables.
Two new paragraphs and one formula adde
Expressiveness modulo Bisimilarity of Regular Expressions with Parallel Composition (Extended Abstract)
The languages accepted by finite automata are precisely the languages denoted
by regular expressions. In contrast, finite automata may exhibit behaviours
that cannot be described by regular expressions up to bisimilarity. In this
paper, we consider extensions of the theory of regular expressions with various
forms of parallel composition and study the effect on expressiveness. First we
prove that adding pure interleaving to the theory of regular expressions
strictly increases its expressiveness up to bisimilarity. Then, we prove that
replacing the operation for pure interleaving by ACP-style parallel composition
gives a further increase in expressiveness. Finally, we prove that the theory
of regular expressions with ACP-style parallel composition and encapsulation is
expressive enough to express all finite automata up to bisimilarity. Our
results extend the expressiveness results obtained by Bergstra, Bethke and
Ponse for process algebras with (the binary variant of) Kleene's star
operation.Comment: In Proceedings EXPRESS'10, arXiv:1011.601
Health-related quality of life (HRQoL) after different axillary treatments in women with breast cancer:a 1-year longitudinal cohort study
Purpose: As life expectancy continues to rise, post-treatment health-related quality of life (HRQoL) of breast cancer patients becomes increasingly important. This study examined the one-year longitudinal relation between axillary treatments and physical, psychosocial, and sexual wellbeing and arm symptoms. Methods: Women diagnosed with breast cancer who received different axillary treatments being axilla preserving surgery (APS) with or without axillary radiotherapy or full axillary lymph node dissection (ALND) with or without axillary radiotherapy were included. HRQoL was assessed at baseline, 6- and 12-months postoperatively using the BREAST-Q and the European Organization for Research and Treatment of Cancer QoL Questionnaire Breast Cancer Module (EORTC QLQ-BR23). Mixed regression models were constructed to assess the impact of axillary treatment on HRQoL. HRQoL at baseline was compared to HRQoL at 6- and at 12-months postoperatively. Results: In total, 552 patients were included in the mixed regressions models. Except for ALND with axillary radiotherapy, no significant differences in physical and psychosocial wellbeing were found. Physical wellbeing decreased significantly between baseline and 6- and 12-months postoperatively (p < 0.001, p = 0.035) and psychosocial wellbeing decreased significantly between baseline and 12 months postoperatively (p = 0.028) for ALND with axillary radiotherapy compared to APS alone. Arm symptoms increased significantly between baseline and 6 months and between baseline and 12 months postoperatively for APS with radiotherapy (12.71, 13.73) and for ALND with radiotherapy (13.93, 16.14), with the lowest increase in arm symptoms for ALND without radiotherapy (6.85, 7.66), compared to APS alone (p < 0.05). Conclusion: Physical and psychosocial wellbeing decreased significantly for ALND with radiotherapy compared to APS alone. Shared decision making and expectation management pre-treatment could be strengthened by discussing arm symptoms per axillary treatment with the patient.</p
Atmospheric parameters and rotational velocities for a sample of Galactic B-type supergiants
High resolution optical spectra of 57 Galactic B-type supergiant stars have
been analyzed to determine their rotational and macroturbulent velocities. In
addition, their atmospheric parameters (effective temperature, surface gravity
and microturbulent velocity) and surface nitrogen abundances have been
estimated using a non-LTE grid of model atmospheres. Comparisons of the
projected rotational velocities have been made with the predictions of stellar
evolutionary models and in general good agreement was found. However for a
small number of targets, their observed rotational velocities were
significantly larger than predicted, although their nitrogen abundances were
consistent with the rest of the sample. We conclude that binarity may have
played a role in generating their large rotational velocities. No correlation
was found between nitrogen abundances and the current projected rotational
velocities. However a correlation was found with the inferred projected
rotational velocities of the main sequence precursors of our supergiant sample.
This correlation is again in agreement with the predictions of single star
evolutionary models that incorporate rotational mixing. The origin of the
macroturbulent and microturbulent velocity fields is discussed and our results
support previous theoretical studies that link the former to sub-photospheric
convection and the latter to non-radial gravity mode oscillations. In addition,
we have attempted to identify differential rotation in our most rapidly
rotating targets.Comment: Submitted to MNRAS, 16 page
Newer long-acting insulin prescriptions for patients with type 2 diabetes: Prevalence and practice variation in a retrospective cohort study
BACKGROUND: Little is known about prescription patterns of expensive non-recommended newer long-acting insulins (glargine 300 U/mL and degludec) for patients with type 2 diabetes mellitus (T2DM). AIM: To identify practice variation in, and practice- and patient-related characteristics associated with, the prescription of newer long-acting insulins to patients with T2DM in primary care. DESIGN AND SETTING: A retrospective cohort study in Dutch general practices (Nivel Primary Care Database). METHOD: A first prescription for intermediate or long-acting insulins in 2018 was identified in patients aged ≥40 years using other T2DM drugs. Per practice, the median percentage and interquartile range (IQR) of patients with newer insulin prescriptions were calculated. Multilevel logistic regression models were constructed to calculate intraclass correlation coefficients (ICCs) and quantify the association of patient and practice characteristics with prescriptions for newer insulins (odds ratios [ORs] and 95% confidence intervals [CIs]). RESULTS: In total, 7757 patients with prescriptions for intermediate or long-acting insulins from 282 general practices were identified. A median percentage of 21.2% (IQR 12.5–36.4%) of all patients prescribed intermediate or long-acting insulins per practice received a prescription for newer insulins. After multilevel modelling, the ICC decreased from 20% to 19%. Female sex (OR 0.77, 95% CI = 0.69 to 0.87), age ≥86 years compared with 40–55 years (OR 0.22, 95% CI = 0.15 to 0.34), prescriptions for metformin (OR 0.66, 95% CI = 0.53 to 0.82), sulfonylurea (OR 0.58, 95% CI = 0.51 to 0.66), or other newer T2DM drugs (OR 3.10, 95% CI = 2.63 to 3.66), and dispensing practices (OR 1.78, 95% CI = 1.03 to 3.10) were associated with the prescription of newer insulins. CONCLUSION: The inter-practice variation in the prescription of newer insulins is large and could only be partially explained by patient- and practice-related differences. This indicates substantial opportunities for improvement
- …