45 research outputs found
On the Pressure Broadening in the Gamma Bands of Nitric Oxide
A quantitative investigation of the pressure broadening in the γ(0,0) and γ(1,0) bands of nitric acid established that the pressure effect is not abnormal as has sometimes been supposed and that the collision diameter of the excited NO molecule is approximately 3.8 Å
In-Datacenter Performance Analysis of a Tensor Processing Unit
Many architects believe that major improvements in cost-energy-performance
must now come from domain-specific hardware. This paper evaluates a custom
ASIC---called a Tensor Processing Unit (TPU)---deployed in datacenters since
2015 that accelerates the inference phase of neural networks (NN). The heart of
the TPU is a 65,536 8-bit MAC matrix multiply unit that offers a peak
throughput of 92 TeraOps/second (TOPS) and a large (28 MiB) software-managed
on-chip memory. The TPU's deterministic execution model is a better match to
the 99th-percentile response-time requirement of our NN applications than are
the time-varying optimizations of CPUs and GPUs (caches, out-of-order
execution, multithreading, multiprocessing, prefetching, ...) that help average
throughput more than guaranteed latency. The lack of such features helps
explain why, despite having myriad MACs and a big memory, the TPU is relatively
small and low power. We compare the TPU to a server-class Intel Haswell CPU and
an Nvidia K80 GPU, which are contemporaries deployed in the same datacenters.
Our workload, written in the high-level TensorFlow framework, uses production
NN applications (MLPs, CNNs, and LSTMs) that represent 95% of our datacenters'
NN inference demand. Despite low utilization for some applications, the TPU is
on average about 15X - 30X faster than its contemporary GPU or CPU, with
TOPS/Watt about 30X - 80X higher. Moreover, using the GPU's GDDR5 memory in the
TPU would triple achieved TOPS and raise TOPS/Watt to nearly 70X the GPU and
200X the CPU.Comment: 17 pages, 11 figures, 8 tables. To appear at the 44th International
Symposium on Computer Architecture (ISCA), Toronto, Canada, June 24-28, 201
Pelvic trauma : WSES classification and guidelines
Complex pelvic injuries are among the most dangerous and deadly trauma related lesions. Different classification systems exist, some are based on the mechanism of injury, some on anatomic patterns and some are focusing on the resulting instability requiring operative fixation. The optimal treatment strategy, however, should keep into consideration the hemodynamic status, the anatomic impairment of pelvic ring function and the associated injuries. The management of pelvic trauma patients aims definitively to restore the homeostasis and the normal physiopathology associated to the mechanical stability of the pelvic ring. Thus the management of pelvic trauma must be multidisciplinary and should be ultimately based on the physiology of the patient and the anatomy of the injury. This paper presents the World Society of Emergency Surgery (WSES) classification of pelvic trauma and the management Guidelines.Peer reviewe
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Uncovering Risk Factors and Outcomes of Pulmonary Embolism in a Nationwide Cohort of Hospitalized Children
PURPOSEThe incidence of pulmonary embolism (PE) in hospitalized children has increased in recent years. This study sought to characterize factors and outcomes associated with PE using a national pediatric cohort.METHODSThe Nationwide Readmissions Database was queried (2016-2018) for patients (12 years old (77%). One-third had a known deep vein thrombosis (69% lower and 31% upper extremity). Nineteen percent underwent central venous catheter (CVC) placement. Twenty-one percent had a PH within 1 year. Nine percent underwent an operation with the majority being cardiothoracic (5%). Overall mortality was 5%. Neurocranial surgery, cardiothoracic surgery, and CVC placement were associated with the highest odds of inpatient mortality after logistic regression.CONCLUSIONPediatric patients with PE have a high rate of PHs, CVC placement, and inpatient operations, which may be associated with higher mortality. This information can be utilized to improve screening measures and clinical suspicion for PE in hospitalized children
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Outcomes of Abdominal Firearm Injury and Damage Control Laparotomy in the Pediatric Population
Firearm injuries (GSW) in the pediatric population is a public health crisis. Little is known about the outcomes of damage control laparotomy (DCL) following abdominal GSW. This study aims to evaluate outcomes from abdominal GSWs in the pediatric population.
The trauma registry from an urban Level 1 trauma was queried for pediatric (0-18 y) GSW was queried from September 2013 to June 2020. Demographics, clinical variables, outcomes, readmissions, and recidivism were analyzed.
Abdominal GSW were identified in 83 patients (17% of all GSW). The median age was 16 [15-17], 84% were male and 86% Black. Violent intent accounted for 90% of GSW. The injury severity score was 16 [9-26] and 80% went directly from the resuscitation bay to the operating room. Laparotomy was required in 87% of patients, and surgery was not required in any patient initially managed nonoperatively. The most common complications were intraabdominal infection (20%), other infections (13%), and small bowel obstruction (8%). DCL with temporary abdominal closure was performed in 16% of laparotomies and was associated with a longer length of stay, more infections, but similar rates of readmission and mortality. Overall mortality was 13%, with all but one patient expiring in the resuscitation bay or the operating room. All patients who underwent DCL survived to discharge.
Abdominal firearm injuries have high morbidity and mortality in the pediatric population. Damage control operations for abdominal GSWs are a valuable surgical option with similar outcomes to primary abdominal closure after initial injury survival
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Outcomes after Ladd Procedures for Intestinal Malrotation in Newborns with Heterotaxy Syndrome
Intestinal malrotation may be asymptomatic in patients with heterotaxy syndrome (HS), and whether these newborns benefit from prophylactic Ladd procedures is unknown. This study sought to uncover nationwide outcomes of newborns with HS receiving Ladd procedures.
Newborns with malrotation were identified from the Nationwide Readmission Database (2010-2014) and stratified into those with and without HS utilizing ICD-9CM codes for situs inversus (759.3), asplenia or polysplenia (759.0), and/or dextrocardia (746.87). Outcomes were analyzed using standard statistical tests.
4797 newborns with malrotation were identified, of which 16% had HS. Ladd procedures were performed in 70% overall and more common in those without heterotaxy (73% vs. 56% HS). Ladd procedures in newborns with heterotaxy were associated with higher complications compared to those without HS including surgical site reopening (8% vs. 1%), sepsis (9% vs. 2%), infections (19% vs. 11%), venous thrombosis (9% vs. 1%), and prolonged mechanical ventilation (39% vs. 22%), all p < 0.001. HS newborns were less frequently readmitted with bowel obstructions (0% vs. 4% without HS, p < 0.001) with no readmissions for volvulus in either group.
Ladd procedures in newborns with heterotaxy were associated with increased complications and cost without differences in rates of volvulus and bowel obstruction on readmission.
Retrospective Comparative.
III
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Underutilization of laparoscopy for ovarian surgeries in the pediatric population: A nationwide analysis
Oophorectomy and ovarian detorsion are some of the most frequent operations performed in the female pediatric population. Despite the advent of laparoscopy, many surgeons continue to utilize open surgical approaches in these patients. This study sought to compare nationwide trends and postoperative outcomes in laparoscopic and open ovarian operations in the pediatric population.
Females less than 21 years old who underwent ovarian operations (oophorectomy, detorsion, and/or drainage) from 2016 to 2017 were identified from the Nationwide Readmissions Database. Patients were stratified by surgical approach (laparoscopic or open). Hospital characteristics and outcomes were compared using standard statistical tests.
There were 13,202 females (age 17 [14–20] years) who underwent open (59%) or laparoscopic (41%) ovarian operations. The most common indications for surgery were ovarian mass (48%), cyst (36%), and/or torsion (19%) for which oophorectomy (88%), detorsion (26%), and drainage (13%) were performed most frequently. The open approach was utilized more frequently for oophorectomy (95% vs. 77% laparoscopic) and detorsion (33% vs. 16% laparoscopic), both p < 0.001. A greater proportion of laparoscopic procedures were performed at large (67% vs. 61% open), teaching (82% vs. 76% open) hospitals in patients with private insurance (47% vs. 42% open), all p < 0.001. Patients undergoing open procedures had significantly higher index length of stay (LOS) and rates of wound infections. Thirty-day and overall readmission rates, as well as overall readmission costs, were higher in patients who received open surgeries.
Despite fewer overall complications, decreased cost, fewer readmissions, and shorter LOS, laparoscopic approaches are underutilized for pediatric ovarian procedures.
Retrospective Comparative.
Level III.
•Oophorectomy and ovarian detorsion are common operations performed in the female pediatric population.•Few studies have directly compared outcomes after laparoscopic and open ovarian operations in the pediatric population.•Despite fewer complications, readmissions, and shorter LOS, laparoscopy is underutilized for pediatric ovarian procedures
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Laparoscopic versus open pyloromyotomies: Outcomes and disparities in pyloric stenosis
Pyloromyotomy for hypertrophic pyloric stenosis (HPS) is one of the most common non-elective operations performed in the neonatal period. This project aims to explore outcomes of pyloromyotomy and compare differences between laparoscopic versus open pyloromyotomies in newborns diagnosed with HPS.
The Nationwide Readmissions Database (NRD) from 2010 to 2014 was queried to identify patients diagnosed with HPS that underwent repair.
In total, 30,915 children (18% female) underwent pyloromyotomy for HPS. Median length of stay for index admission was 2 days. A total of 212 (0.7%) patients required a redo pyloromyotomy. 127 (60%) were performed during index admission. Readmission rate at 30 days was 3% and 5% at one year, and 22% presented to a different hospital. The most common indications for readmission were feeding intolerance (24%), dehydration (10%), and malnutrition (10%). Patients from low-income households were more likely to present with malnutrition and weight loss (9% vs 4%, p<0.001) and had higher readmission rates (8% vs 4%, p<0.001). Laparoscopic pyloromyotomies accounted for 10% (n = 2951) of cases. Those undergoing laparoscopy were less likely to have electrolyte disturbances (41% vs 54%, p<0.001) or weight loss (2% vs 11%, p<0.001) on admission. The rate of open conversion was 1%. Intraoperative perforation was not more common in laparoscopic than open cases. Open pyloromyotomies had higher 30-day readmission rates and more surgical site infections.
Complications from pyloromyotomies are rare. Although infrequent, the incidence of incomplete pyloromyotomy is higher than previously reported and more common with open approaches. Newborns from low-income households are more likely to present with advanced symptoms and have disproportionately higher rates of readmission.
Level III
Treatment Study, retrospectiv