2,691 research outputs found
The Bohl spectrum for nonautonomous differential equations
We develop the Bohl spectrum for nonautonomous linear differential equation
on a half line, which is a spectral concept that lies between the Lyapunov and
the Sacker--Sell spectrum. We prove that the Bohl spectrum is given by the
union of finitely many intervals, and we show by means of an explicit example
that the Bohl spectrum does not coincide with the Sacker--Sell spectrum in
general. We demonstrate for this example that any higher-order nonlinear
perturbation is exponentially stable, although this not evident from the
Sacker--Sell spectrum. We also analyze in detail situations in which the Bohl
spectrum is identical to the Sacker-Sell spectrum
The structurally stable linear systems on the half-line are those with exponential dichotomies
An ordering for linear differential systems and a characterization of exponential separation in terms of reducibility
Factors Affecting Color of Cured Burley Leaf
Much interest has been shown by tobacco growers during recent months in fertilization and or other management practices that can be used to produce darker and redder cured leaf of burley tobacco. The purpose of this newsletter is to summarize what we know about some of the factors which affect color of cured leaf
Characteristics and survival of patients with advanced cancer and p53 mutations.
P53 mutations are associated with invasive tumors in mouse models. We assessed the p53mutations and survival in patients with advanced cancer treated in the Phase I Program. Of 691 tested patients, 273 (39.5%) had p53 mutations. Patients with p53 mutations were older (p<.0001) and had higher numbers of liver metastases (p=.005). P53 mutations were associated with higher numbers of other aberrations; PTEN (p=.0005) and HER2 (p=.003)aberrations were more common in the p53 mutation group. No survival difference was observed between patients with p53 mutations and those with wild-type p53. In patients with wild-type p53 and other aberrations, patients treated with matched-therapy against the additional aberrations had longer survival compared to those treated with non-matched-therapy or those who received no therapy (median survival, 26.0 vs. 11.8 vs. 9.8 months, respectively; p= .0007). Results were confirmed in a multivariate analysis (p= .0002). In the p53 mutation group with additional aberrations, those who received matched-therapy against the additional aberrations had survival similar to those treated with non-matched-therapy or those who received no therapy (p=.15). In conclusion, our results demonstrated resistance to matched-targeted therapy to the other aberrations in patients with p53 mutations and emphasize the need to overcome this resistance
Baring one’s soul in narrative health research: the enculturation of a health care professional in an island population
Autoethnography demands a high degree of self-reflection and openness about one’s own life that is both disconcerting and necessary. Therefore, the presentation of self becomes necessary to inform the reader about the author’s positionality in research, but without overextending its scope to the extraneous or sensitive. The utility of the narrative form in autoethnography is discussed in this paper revolving around four short stories including: 1. Starting Points, 2. Arrival, 3. Transition to Care Work and Nursing, and 4.
Professional Initiation. These auto-narratives are part of a wider study into the enculturation of a health care professional in an island population. These progressive and linked accounts are counterpointed with metanarrative as reflexive explanation of how autoethnography has been deployed as research method. Our paper highlights the potential contribution of autoethnography and narrative research to health practitioners working in socio-cultural and clinical settings. The field in this research is the Isle of Wight, off the south coast of the United Kingdom. Key themes related to this location include its geographical position (i.e. its relative isolation to the mainland), and its role as a social-demographic outlier as foretaste of the future population that the National Health Service will serve (i.e. it’s high percentage of retired and elderly people). Consequently there is a wide variance in healthcare needs represented in the Island’s population, which are placing new demands on the healthcare workforce to meet those needs in the community. Our paper concludes that the narrative turn through this research is yielding positive insights to how health care is received by those whom it is intended to help, and importantly therefore, how health care professionals might alter their practice in the future, to enhance social approaches in clinical care and therefore to maximize the positive impacts of their actions. NB: The first author is a PhD by Portfolio candidate at the University of Central Lancashire. PhD by Portfolio requires a collation of personal experiences and professional attainments, upon which a ‘retrospective’ reflective critique of can be made, in order to guide and inform a new ‘prospective’ phase of research. This article is part of that process
Outcomes of patients with advanced cancer and KRAS mutations in phase I clinical trials.
BackgroundKRAS mutation is common in human cancer. We assessed the clinical factors, including type of KRAS mutation and treatment, of patients with advanced cancer and tumor KRAS mutations and their association with treatment outcomes.MethodsPatients referred to the Phase I Clinic for treatment who underwent testing for KRAS mutations were analyzed.ResultsOf 1,781 patients, 365 (21%) had a KRAS mutation. The G12D mutation was the most common mutation (29%). PIK3CA mutations were found in 24% and 10% of patients with and without KRAS mutations (p<0.0001). Of 223 patients with a KRAS mutation who were evaluable for response, 56 were treated with a MEK inhibitor-containing therapy and 167 with other therapies. The clinical benefit (partial response and stable disease lasting ≥6 months) rates were 23% and 9%, respectively, for the MEK inhibitor versus other therapies (p=0.005). The median progression-free survival (PFS) was 3.3 and 2.2 months, respectively (p=0.09). The respective median overall survival was 8.4 and 7.0 months (p=0.38). Of 66 patients with a KRAS mutation and additional alterations, higher rates of clinical benefit (p=0.04), PFS (p=0.045), and overall survival (p=0.02) were noted in patients treated with MEK inhibitor-containing therapy (n=9) compared to those treated with targeted therapy matched to the additional alterations (n=24) or other therapy (n=33).ConclusionsMEK inhibitors in patients with KRAS-mutated advanced cancer were associated with higher clinical benefit rates compared to other therapies. Therapeutic strategies that include MEK inhibitors or novel agents combined with other targeted therapies or chemotherapy need further investigation
Patterns and predictors of smoking by race and medical diagnosis during hospital admission: A latent class analysis
Hospital-based tobacco treatment programs provide tobacco cessation for a diverse array of admitted patients. Person-centered approaches to classifying subgroups of individuals within large datasets are useful for evaluating the characteristics of the sample. This study categorized patients who received tobacco treatment while hospitalized and determined whether demographics and smoking-related health conditions were associated with group membership. Chart review data was obtained from 4854 patients admitted to a large hospital in South Carolina, USA, from July 2014 through December 2019 who completed a tobacco treatment visit. Smoking characteristics obtained from the visit interview were dichotomized, and then latent class analysis (LCA) was conducted to categorize patients based on smoking history and interest in stopping smoking. Finally, logistic regressions were used to evaluate demographics and smoking-related health conditions as predictors of class membership. LCA generated 5 classes of patients, differentiated by heaviness of smoking and motivation to quit. Patients who were black/African American were more likely to be lighter smokers compared to white patients. Hospitalized patients with a history of hypertension, diabetes, and congestive heart failure were more likely to be motivated to quit and also were more likely to be lighter smokers at the time of hospitalization. Hospitalized patients who smoke and receive tobacco treatment are heterogeneous in terms of their smoking histories and motivation to quit. Understanding latent categories of patients provides insight for tailoring interventions and potentially improving tobacco treatment outcomes
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