2,822 research outputs found
The Formation of Brown Dwarfs: Observations
We review the current state of observational work on the formation of brown
dwarfs, focusing on their initial mass function, velocity and spatial
distributions at birth, multiplicity, accretion, and circumstellar disks. The
available measurements of these various properties are consistent with a common
formation mechanism for brown dwarfs and stars. In particular, the existence of
widely separated binary brown dwarfs and a probable isolated proto-brown dwarf
indicate that some substellar objects are able to form in the same manner as
stars through unperturbed cloud fragmentation. Additional mechanisms such as
ejection and photoevaporation may play a role in the birth of some brown
dwarfs, but there is no observational evidence to date to suggest that they are
the key elements that make it possible for substellar bodies to form.Comment: Protostars and Planets V, in pres
Improving Postoperative Pain Control After Cesarean Delivery with Enhanced Recovery in Patients on Buprenorphine Therapy
Abstract:
Introduction:
Prescription drug abuse presents a significant challenge to the management of post operative pain.Pain control amongst the opioid addicted patient can be especially challenging. We aimed to improve pain control after caesarian delivery with enhanced recovery in patients who are on buprenorphine medication-assisted therapy for the treatment of opioid addiction.
Materials and Methods:
We conducted a pilot study by implementing a protocol using liposomal bupivacaine injected at the time of cesarean delivery. Patients were then given 500mg acetaminophen every 4 hours, 800mg ibuprofen every 8 hours and 0.3mg IV buprenorphine every 6 hours as needed. The patients’ maintenance dosing of buprenorphine was divided into doses throughout the day. In addition, patients were ambulated 4 hours after surgery and had their catheter removed from their bladder as soon as they could safely ambulate. Eleven patients were prospectively recruited and then compared to a retrospective sample of seventeen patients.
Results:
Patients in the treatment group reported 27% lower pain scores (p
Discussion:
Our enhanced recovery protocol is an effective alternative to traditional pain control and is associated with a significant reduction in both pain scores and use of breakthrough IV buprenorphine as well as lower charges
Magneto-optical spectra of closely spaced magnetite nanoparticles
The Faraday rotation spectrum of composites containing magnetite nanoparticles is found to be dependent on the interparticle spacing of the constituent nanoparticles. The composite materials are prepared by combining chemically synthesized Fe
3O4 smagnetited nanoparticles s8-nm diameterd and polysmethylmethacrylated . Composites are made containing a range of nanoparticle concentrations. The peak of the main spectral feature depends on nanoparticle concentration; this peak is observed to shift from approximately 470 nm for sdilute compositesd to 540 nm concentrated . We present a theory based on the discrete-dipole approximation which accounts for
optical coupling between magnetite particles. Qualitative correlations between theoretical calculations and experimental data suggest that the shifts in spectral peak position depend on both interparticle distance and geometrical configuratio
Reducing Postoperative Opioids After Minimally Invasive Hysterectomy with Enhanced Recovery
I
Introduction:
We evaluated the efficacy of various strategies utilized for the control of postoperative pain after minimally invasive hysterectomy. The primary enhanced recovery after surgery (ERAS) protocol of interest utilized premedication (acetaminophen, celecoxib and pregabalin), then intraoperative subcutaneous liposomal bupivacaine followed by scheduled oral acetaminophen and ibuprofen postoperatively. Patients also had tramadol and oxycodone as needed for moderate or severe breakthrough pain, respectively.
Materials and Methods:
We conducted a retrospective cohort study that included all patients who underwent minimally invasive hysterectomy (total laparoscopic hysterectomy and laparoscopic-assisted vaginal hysterectomy) for both benign and oncologic indications over a 2-year period. We then compared six protocols, with 3 being ERAS protocols and 3 as traditional pain control methods. The control group was comprised of the traditional pain control group without intraoperative placement of local analgesia. Patient medical records were evaluated for demographics, surgical characteristics, opioid type and dose, pain scores, length of stay and complications. Opioids were converted to oral morphine dose equivalents.
Results:
954 patients were included within the 6 protocols. Median opioid usage was the lowest in the ERAS group with premedication and highest in the control group (22.5mg versus 55.0mg, p
Discussion:
ERAS protocol with premedication was associated with significant reductions in postoperative opioid use and median pain scores when compared to traditional methods
Connecting massive galaxies to dark matter halos in BOSS - I. Is galaxy color a stochastic process in high-mass halos?
We use subhalo abundance matching (SHAM) to model the stellar mass function
(SMF) and clustering of the Baryon Oscillation Spectroscopic Survey (BOSS)
"CMASS" sample at . We introduce a novel method which accounts for
the stellar mass incompleteness of CMASS as a function of redshift, and produce
CMASS mock catalogs which include selection effects, reproduce the overall SMF,
the projected two-point correlation function , the CMASS ,
and are made publicly available. We study the effects of assembly bias above
collapse mass in the context of "age matching" and show that these effects are
markedly different compared to the ones explored by Hearin et al. (2013) at
lower stellar masses. We construct two models, one in which galaxy color is
stochastic ("AbM" model) as well as a model which contains assembly bias
effects ("AgM" model). By confronting the redshift dependent clustering of
CMASS with the predictions from our model, we argue that that galaxy colors are
not a stochastic process in high-mass halos. Our results suggest that the
colors of galaxies in high-mass halos are determined by other halo properties
besides halo peak velocity and that assembly bias effects play an important
role in determining the clustering properties of this sample.Comment: 22 pages. Appendix. B added. Matches the version accepted by MNRAS.
Mock galaxy catalog and HOD table are available at
http://www.massivegalaxies.co
Linking Wolf Diet to Changes in Marine and Terrestrial Prey Abundance
Since most wolf (Canis lupus) diet studies have been conducted in inland ecosystems, comparatively few data are available on diets of wolves in coastal systems. We investigated the diet of wolves in Glacier Bay, Alaska, from 12 May to 28 June in both 2010 and 2011. Although we identified 12 different prey species, including birds and small to medium-sized mammals, in wolf scats, moose (Alces alces) was the most frequent food item, observed in 80% of all scats. In contrast, a study conducted in 1993 in an area 37 km away found harbor seal (Phoca vitulina richardii) in 41% of wolf scats. Although we cannot account for differences in sampling design between the two studies, wolf diets may have changed between the two time periods.Puisque la plupart des études sur le régime alimentaire des loups (Canis lupus) ont été réalisées dans des écosystèmes situés à l’intérieur des terres, relativement peu de données existent sur le régime alimentaire des loups évoluant dans les environnements côtiers. Nous avons étudié l’alimentation des loups de Glacier Bay, en Alaska, du 12 mai au 28 juin 2010 et 2011. Bien que nous ayons retrouvé 12 proies différentes, y compris des espèces aviaires et des mammifères de taille petite ou de taille moyenne dans les déjections de loups, l’aliment le plus fréquemment rencontré, dans une mesure de 80 %, a été l’original, aussi appelé élan (Alces alces). Par contraste, une étude effectuée en 1993 dans une zone située à 37 kilomètres de distance a permis de découvrir du phoque commun (Phoca vitulina richardii) dans 41 % des déjections de loups. Bien que nous ne soyons pas en mesure de prendre en compte les différences d´échantillonnage entre les deux études, il est possible que le régime alimentaire des loups ait changé entre ces deux périodes.Большинство исследований рациона волка (Canis lupus) проводилось на внутриматериковых территориях, в то время как имеется сравнительно небольшое количество данных по рациону волка в прибрежных экосистемах. Ежегодно с 12 мая по 28 июня 2010-2011 гг. нашей группой проводились исследования рациона волков в бухте Глейшер-Бей, Аляска. Несмотря на то, что нами было определено 12 различных видов, используемых волками в качестве добычи, включая птиц, а также мелких и средних млекопитающих, останки лося (Alces alces) встречались в 80% экскрементов волков, указывая на то, что данный вид является наиболее частым пищевым объектом волка.В отличие от данных результатов, эксперимент, проведенный в 1993 г. на участке, удаленном от нашего на 37 км, обнаружил наличие останков тюленя (Phoca vitulina richardii) в 41% экскрементов волков. Несмотря на то, что мы не можем объяснить различия в выборке по каждому из исследований, их результаты указывают на то, что в период между двумя исследованиями в рационе волков могли произойти изменения
Effects of word predictability on eye movements during Arabic reading
Contextual predictability influences both the probability and duration of eye fixations on words when reading Latinate alphabetic scripts like English and German. However, it is unknown whether word predictability influences eye movements in reading similarly for Semitic languages like Arabic, which are alphabetic languages with very different visual and linguistic characteristics. Such knowledge is nevertheless important for establishing the generality of mechanisms of eye-movement control across different alphabetic writing systems. Accordingly, we investigated word predictability effects in Arabic in two eye-movement experiments. Both produced shorter fixation times for words with high compared to low predictability, consistent with previous findings. Predictability did not influence skipping probabilities for (four- to eight-letter) words of varying length and morphological complexity (Experiment 1). However, it did for short (three- to four-letter) words with simpler structures (Experiment 2). We suggest that word-skipping is reduced, and affected less by contextual predictability, in Arabic compared to Latinate alphabetic reading, because of specific orthographic and morphological characteristics of the Arabic script
CD4+ lymphocyte adenosine triphosphate determination in sepsis: a cohort study
INTRODUCTION: Patients suffering from sepsis are currently classified on a clinical basis (i.e., sepsis, severe sepsis, septic shock); however, this clinical classification may not accurately reflect the overall immune status of an individual patient. Our objective was to describe a cohort of patients with sepsis in terms of their measured immune status. METHODS: Fifty-two patients with sepsis (n = 13), severe sepsis (n = 21), or septic shock (n = 18) were studied. The immune status was determined by measuring the CD4+ lymphocyte adenosine triphosphate (ATP) content after mitogen stimulation in whole blood. RESULTS: The measured CD4+ lymphocyte ATP content at the time of ICU admission did not differ among the various groups defined by the sepsis classification system (sepsis = 454 ± 79 ng/ml; severe sepsis = 359 ± 54 ng/ml; septic shock = 371 ± 53 ng/ml; P = 0.44). Furthermore, survivors of sepsis had a significantly higher CD4+ lymphocyte ATP content at the time of ICU admission than did nonsurvivors of sepsis (431 ± 41 ng/mL vs. 266 ± 53 ng/mL, respectively; P = 0.04). CONCLUSIONS: The sepsis classification system that is currently used is not representative of the individual immune status as determined by measuring the CD4+ lymphocyte ATP content. Moreover, a lower CD4+ ATP content at the time of ICU admission is associated with a worse clinical outcome in those suffering from sepsis
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