1,521 research outputs found
Perspectives on Firm Decision Making During Risky Technology Acquisitions
A novel survey dataset on computed tomography (CT) machine acquisition is used to explore which theories best answer two questions from the decision making literature. First, what determines how much uncertainty a firm has when investing in updated technology? Second, what determines the value of the acquisition? In answering these questions, two theoretical comparisons are conducted. In the first, economic theory, behavioral theory (the Behavioral Theory of the Firm and Prospect Theory), and Bounded Rationality are tested as potential determinants of acquisition uncertainties. In the second, economic theory and Prospect Theory are tested as potential determinants of the value of the machine acquired.
To answer these questions, hospitals were surveyed about the acquisition of their most valuable computed tomography machine. From the survey data, support was found for the Bounded Rationality hypothesis; firms have less uncertainty about an acquisition’s performance on attributes that correspond to more strongly held objectives. Support was also found for the behavioral theory hypothesis; firms whose prior machines perform below aspiration levels seek more uncertainty in their subsequent acquisitions, while firms whose machines perform above aspiration levels seek less uncertainty. No support was found for the normative hypothesis; acquisition uncertainty is determined by economic attributes.
In the second comparison, partial support was found for the normative theory hypothesis and no support was found for Prospect Theory hypothesis. The value of the acquisition increased as the minimum lifespan of the acquisition increased. Perceived revenue, operating cost, and financial factor uncertainty did not significantly influence acquisition value, providing no support for Prospect Theory. However, greater uncertainty over the acquisition’s ability to fulfill customer desires was associated with the acquisition of a less expensive machine.
Studies of the influence of uncertainty on capital investment decision making have traditionally focused on financial forms of uncertainty. The results of this study suggest that the influence of uncertainty related to an acquisition’s ability to fulfill customer desires may have an even stronger influence on the value of an acquisition than variables related to the non-perceptual characteristics of the acquirer
Enhanced Cellular Immunity in Shrimp (Litopenaeus vannamei) after ‘Vaccination’
It has long been viewed that invertebrates rely exclusively upon a wide variety of innate mechanisms for protection from disease and parasite invasion and lack any specific acquired immune mechanisms comparable to those of vertebrates. Recent findings, however, suggest certain invertebrates may be able to mount some form of specific immunity, termed ‘specific immune priming’, although the mechanism of this is not fully understood (see Textbox S1). In our initial experiments, either formalin-inactivated Vibrio harveyi or sterile saline were injected into the main body cavity (haemocoel) of juvenile shrimp (Litopenaeus vannamei). Haemocytes (blood cells) from V. harveyi-injected shrimp were collected 7 days later and incubated with a 1∶1 mix of V. harveyi and an unrelated Gram positive bacterium, Bacillus subtilis. Haemocytes from ‘vaccinated’ shrimp showed elevated levels of phagocytosis of V. harveyi, but not B. subtilis, compared with those from saline-injected (non-immunised) animals. The increased phagocytic activity was characterised by a significant increase in the percentage of phagocytic cells. When shrimp were injected with B. subtilis rather than vibrio, there was no significant increase in the phagocytic activity of haemocytes from these animals in comparison to the non-immunised (saline injected) controls. Whole haemolymph (blood) from either ‘immunised’ or non-immunised’ shrimp was shown to display innate humoral antibacterial activity against V. harveyi that was absent against B. subtilis. However, there was no difference in the potency of antibacterial activity between V. harveyi-injected shrimp and control (saline injected) animals showing that ‘vaccination’ has no effect on this component of the shrimp's immune system. These results imply that the cellular immune system of shrimp, particularly phagocytosis, is capable of a degree of specificity and shows the phenomenon of ‘immune priming’ reported by other workers. However, in agreement with other studies, this phenomenon is not universal to all potential pathogens
Mitigating Electronic Current in Molten Flux for the Magnesium SOM Process
The solid oxide membrane (SOM) process has been used at 1423 K to 1473 K (1150 °C to 1200 °C) to produce magnesium metal by the direct electrolysis of magnesium oxide. MgO is dissolved in a molten MgF[subscript 2]-CaF[subscript 2] ionic flux. An oxygen-ion-conducting membrane, made from yttria-stabilized zirconia (YSZ), separates the cathode and the flux from the anode. During electrolysis, magnesium ions are reduced at the cathode, and Mg[subscript (g)] is bubbled out of the flux into a separate condenser. The flux has a small solubility for magnesium metal which imparts electronic conductivity to the flux. The electronic conductivity decreases the process current efficiency and also degrades the YSZ membrane. Operating the electrolysis cell at low total pressures is shown to be an effective method of reducing the electronic conductivity of the flux. A two steel electrode method for measuring the electronic transference number in the flux was used to quantify the fraction of electronic current in the flux before and after SOM process operation. Potentiodynamic scans, potentiostatic electrolyses, and AC impedance spectroscopy were also used to characterize the SOM process under different operating conditions.National Science Foundation (U.S.) (Grant No. 102663)United States. Dept. of Energy (Grant No. DE-EE0005547
Outpatient facility-based order variation in combined imaging.
OBJECTIVE: Combined computed tomography (CT) occurs when one anatomical area is simultaneously imaged both without and with contrast, or two overlapping anatomical areas are imaged concurrently. While this has been studied in a Traditional Medicare population, it has not been studied in other populations subject to prior authorization. This study explores between-facility variation in ordering and receiving orders to render combined CT in a mixed commercial and Medicare Advantage population.
METHODS: Orders for CT abdomen (without/with contrast), CT thorax (without/with contrast), and concurrent CT brain and sinus authorized by a prior authorization company from 2013-2017, pertaining to patients with commercial or Medicare Advantage health plans from one national insurer, were extracted. Orders were issued and rendered by both hospitals and nonhospitals. The analysis was performed separately for each anatomical area in two ways: orders were grouped by ordering facility, and by designated rendering facility. For each facility, the ratio of combined to total orders was calculated, and analysis of variance was used to determine whether there were significant differences in this rate by year. The association between health plan type and combined imaging rates was assessed.
RESULTS: Combined rates [ratio±standard deviation] for abdomen, thorax, and brain/sinus were 0.306±0.246, 0.089±0.142, and 0.002±0.01 respectively when the analysis was conducted according to ordering facility, and 0.311±0.178, 0.096±0.113, and 0.001±0.006 when the analysis was conducted according to designated rendering facility. Combined CT abdomen and CT thorax rates decreased monotonically from 2013 to 2017, decreases that were significant (P \u3c .01) regardless of whether orders were grouped by ordering or rendering facility. Combined CT abdomen and CT thorax rates significantly differed between orders pertaining to people with commercial and Medicare Advantage plans.
DISCUSSION: Variability was greater when orders were grouped by ordering facility, rather than rendering facility. Health plan type may influence whether a patient receives combined CT
Recommended from our members
Interrater Reliability of mHealth App Rating Measures: Analysis of Top Depression and Smoking Cessation Apps
Background: There are over 165,000 mHealth apps currently available to patients, but few have undergone an external quality review. Furthermore, no standardized review method exists, and little has been done to examine the consistency of the evaluation systems themselves.
Objective: We sought to determine which measures for evaluating the quality of mHealth apps have the greatest interrater reliability.
Methods: We identified 22 measures for evaluating the quality of apps from the literature. A panel of 6 reviewers reviewed the top 10 depression apps and 10 smoking cessation apps from the Apple iTunes App Store on these measures. Krippendorff’s alpha was calculated for each of the measures and reported by app category and in aggregate.
Results: The measure for interactiveness and feedback was found to have the greatest overall interrater reliability (alpha=.69). Presence of password protection (alpha=.65), whether the app was uploaded by a health care agency (alpha=.63), the number of consumer ratings (alpha=.59), and several other measures had moderate interrater reliability (alphas>.5). There was the least
agreement over whether apps had errors or performance issues (alpha=.15), stated advertising policies (alpha=.16), and were easy to use (alpha=.18). There were substantial differences in the interrater reliabilities of a number of measures when they were applied to depression versus smoking apps.
Conclusions: We found wide variation in the interrater reliability of measures used to evaluate apps, and some measures are more robust across categories of apps than others. The measures with the highest degree of interrater reliability tended to be those that involved the least rater discretion. Clinical quality measures such as effectiveness, ease of use, and performance had relatively
poor interrater reliability. Subsequent research is needed to determine consistent means for evaluating the performance of apps. Patients and clinicians should consider conducting their own assessments of apps, in conjunction with evaluating information
from reviews
The Role of Visual Sensory Performance Outcomes in Concussions: Impact on Concussed Special Operations Forces Combat Soldiers and Possible Implications for the Future of Sports-Related Concussions
The Role of Visual Sensory Performance Outcomes in Concussions: Impact on Concussed Special Operations Forces Combat Soldiers and Possible Implications for the Future of Sports-Related Concussions
Clara Soligon, BS, CAT(C)
Concordia University, 2022
This thesis details the increased concern towards concussions in athletes and Soldiers as well as the role of visual sensory performance. More studies are showing the consequences, whether short term or long term, of concussions. The symptoms burden and multiple neurocognitive deficits faced by a concussed athlete are getting increasingly recognized by society, as well as healthcare professionals. Studies have shown how concussions can also cause visual sensory performance deficits, even when traditional assessments are normal, and the athletes are cleared to return to play. One big challenge with concussions is the lack of objective measures to diagnose a concussion, as well for medically clearing an athlete or Soldier to return to full activity. Even with the knowledge that visual deficits might be present after a concussion; most traditional assessments do not assess vision due to a lack of unified platform and test availability. Visual sensory performance is important for injury prevention and impact anticipation, as well as assuring peak occupational performance. We assessed US Special Operations Forces combat Soldiers’ visual sensory performance outcomes. Concussions are the most common traumatic injury in the US military since 2000. Visual sensory performance outcome deficits could prevent Soldiers to complete their missions and impact their safety. Finding visual sensory performance outcomes deficits could help prevent an early return to play or return to duty, an increased risk of re-injury as well as help guide rehabilitation in athletes and military alike
Recommended from our members
Phenotypic heterogeneity and genetic modification of P102L inherited prion disease in an international series
The largest kindred with inherited prion disease P102L, historically Gerstmann-Sträussler-Scheinker syndrome, originates from central England, with émigrés now resident in various parts of the English-speaking world. We have collected data from 84 patients in the large UK kindred and numerous small unrelated pedigrees to investigate phenotypic heterogeneity and modifying factors. This collection represents by far the largest series of P102L patients so far reported. Microsatellite and genealogical analyses of eight separate European kindreds support multiple distinct mutational events at a cytosine-phosphate diester-guanidine dinucleotide mutation hot spot. All of the smaller P102L kindreds were linked to polymorphic human prion protein gene codon 129M and were not connected by genealogy or microsatellite haplotype background to the large kindred or each other. While many present with classical Gerstmann-Sträussler-Scheinker syndrome, a slowly progressive cerebellar ataxia with later onset cognitive impairment, there is remarkable heterogeneity. A subset of patients present with prominent cognitive and psychiatric features and some have met diagnostic criteria for sporadic Creutzfeldt-Jakob disease. We show that polymorphic human prion protein gene codon 129 modifies age at onset: the earliest eight clinical onsets were all MM homozygotes and overall age at onset was 7 years earlier for MM compared with MV heterozygotes (P = 0.02). Unexpectedly, apolipoprotein E4 carriers have a delayed age of onset by 10 years (P = 0.02). We found a preponderance of female patients compared with males (54 females versus 30 males, P = 0.01), which probably relates to ascertainment bias. However, these modifiers had no impact on a semi-quantitative pathological phenotype in 10 autopsied patients. These data allow an appreciation of the range of clinical phenotype, modern imaging and molecular investigation and should inform genetic counselling of at-risk individuals, with the identification of two genetic modifiers
Daily life stress and the cortisol awakening response : testing the anticipation hypothesis
Acknowledgments We thank Paul Stewart for his contribution to data collection and Dr Matthew Jones for programming the handheld computers. Author Contributions Conceived and designed the experiments: WS DJP. Performed the experiments: DJP. Analyzed the data: WS. Wrote the paper: WS DJP.Peer reviewedPublisher PD
The Two Variables in The Triple System HR 6469=V819 Her: One Eclipsing, One Spotted
A complete BV light curve, from 14 nights of good data obtained with the Vanderbilt University-Tennessee State University (VU-TSU) automatic telescope, are presented and solved with the Wilson-Devinney program. Third light is evaluated, with the companion star brighter by 0.58m in V and 0.11m in B. The eclipses are partial. Inferred color indices yield F2 V and F8 V for the eclipsing pair and G8 IV-III for the distant companion star. After removing the variability due to eclipses, we study the residual variability of the G8 IV-III star over the ten years 1982 to 1992. Each yearly light curve is fit with a two-spot model. Three relatively long-lived spots are identified, with rotation periods of 85.9d, 85.9d, and 86.1d. The weak and intermittent variability is understood because the G8 IV-III star has a Rossby number at the threshold for the onset of heavy spottedness
Comparing pediatric gastroenteritis emergency department care in Canada and the United States
BACKGROUND: Between-country variation in health care resource use and its impact on outcomes in acute care settings have been challenging to disentangle from illness severity by using administrative data. METHODS: We conducted a preplanned analysis employing patient-level emergency department (ED) data from children enrolled in 2 previously conducted clinical trials. Participants aged 3 to,48 months with,72 hours of gastroenteritis were recruited in pediatric EDs in the United States (N = 10 sites; 588 participants) and Canada (N = 6 sites; 827 participants). The primary outcome was an unscheduled health care provider visit within 7 days; the secondary outcomes were intravenous fluid administration and hospitalization at or within 7 days of the index visit. RESULTS: In adjusted analysis, unscheduled revisits within 7 days did not differ (adjusted odds ratio [aOR]: 0.72; 95% confidence interval (CI): 0.50 to 1.02). At the index ED visit, although participants in Canada were assessed as being more dehydrated, intravenous fluids were administered more frequently in the United States (aOR: 4.6; 95% CI: 2.9 to 7.1). Intravenous fluid administration rates did not differ after enrollment (aOR: 1.4; 95% CI: 0.7 to 2.8; US cohort with Canadian as referent). Overall, intravenous rehydration was higher in the United States (aOR: 3.8; 95% CI: 2.5 to 5.7). Although hospitalization rates during the 7 days after enrollment (aOR: 1.1; 95% CI: 0.4 to 2.6) did not differ, hospitalization at the index visit was more common in the United States (3.9% vs 2.3%; aOR: 3.2; 95% CI: 1.6 to 6.8). CONCLUSIONS: Among children with gastroenteritis and similar disease severity, revisit rates were similar in our 2 study cohorts, despite lower rates of intravenous rehydration and hospitalization in Canadian-based EDs
- …