243 research outputs found

    IMPLEMENTATION OF THE SINGLE FUEL CONCEPT FOR THE NAVY'S SURFACE FLEET: AN ANALYSIS OF LONG-TERM SOLUTIONS

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    The U.S. Navy’s surface fleet has been operating on two primary types of fuel for several decades, F-76 for ships and JP-5 for maritime aircraft. Since the implementation of these two fuels, multiple research projects have been conducted to recommend a Single Fuel Concept (SFC), but the Navy has not changed its fuel concept. In today's environment, the Navy needs solutions to cut costs and simplify the supply chain in an effort to focus on the Great Power Competition (GPC) while being mindful of defense budget constraints. Over the past several years, the JP-5 and F-76 price differential has decreased significantly, which provides an opportunity to implement an SFC based on cost benefits. This paper conducts regression analyses on both types of fuel and predicts consumption trends for the future based on the large fleet expansion set forth by the 30-Year Shipbuilding Plan. Cost and standard pricing metrics are used to show the possible cost savings by using JP-5 as a single fuel across the fleet. Implementation of an SFC will take time, especially with a growing fleet, so a phased rollout plan was developed to recommend timeframes for introduction of the SFC while mitigating risk to the fleet. This thesis recommends immediate implementation of the SFC in a phased rollout in order to cut costs, simplify the supply chain, and provide a long-term solution to a growing logistics problem.Monterey, CA, 93943Lieutenant, United States NavyLieutenant, United States NavyApproved for public release. Distribution is unlimited

    Hallucinations Are Real to Patients With Dementia

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    In this case study, we present a patient with preexistent posttraumatic stress disorder and psychosis who has been recently diagnosed with Dementia with Lewy Bodies. He is experiencing vivid hallucinations. What went wrong between him and his wife as a result of these hallucinations is presented. Alternative actions that could have been used are suggested

    Primary cervical malignant teratoma with a rib metastasis in an adult: Five-year survival after surgery and chemotherapy: A case report with a review of the literature

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    We report a case of a man presenting with a cervical malignant teratoma and a chondrosarcomatous rib metastasis. He was alive and free of recurrence five years and 10 months (= 70 months) after resection of the primary mass, followed by chemotherapy and subsequent resection of the rib tumor. This is the 35th patient reported in the literature and the first description in which an ‘adjuvant' or primary chemotherapy was used. Previous patients with a cervical malignant teratoma, reported after lethal outcome, had survivals of one to 22 months (median nine months). In all patients with a preoperative clinical impression of an aggressive, differentiated or undifferentiated malignancy, the definite diagnosis of teratoma could only be made histologically. By analogy to germ cell tumors, the prognosis of malignant teratoma might be improved if complete excision is combined with new, adjuvant chemotherapy protocols for germ cell tumors. Lessons learned from this case are placed in the context of germ cell tumors in general and of non-gonadal malignant teratomas in particula

    A Likelihood Ratio Test for Changes in Homeolog Expression Bias

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    Background Gene duplications are a major source of raw material for evolution and a likely contributor to the diversity of life on earth. Duplicate genes (i.e., homeologs, in the case of a whole genome duplication) may retain their ancestral function, sub- or neofunctionalize, or be lost entirely. A primary way that duplicate genes evolve new functions is by altering their expression patterns. Comparing the expression patterns of duplicate genes gives clues as to whether any of these evolutionary processes have occurred. Results We develop a likelihood ratio test for the analysis of the expression ratios of duplicate genes across two conditions (e.g., tissues). We demonstrate an application of this test by comparing homeolog expression patterns of 1448 homeologous gene pairs using RNA-seq data generated from leaves and petals of an allotetraploid monkeyflower (Mimulus luteus). We assess the sensitivity of this test to different levels of homeolog expression bias and compare the method to several alternatives. Conclusions The likelihood ratio test derived here is a direct, transparent, and easily implemented method for detecting changes in homeolog expression bias that outperforms alternative approaches. While our method was derived with homeolog analysis in mind, this method can be used to analyze changes in the ratio of expression levels between any two genes in any two conditions

    Driving and Patients With Dementia

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    Driving is a symbol of autonomy and independence, eagerly awaited during adolescence, cherished during adulthood and reluctantly rescinded during old age. It is nevertheless an individual’s privilege, not right, especially as driving may affect other drivers and pedestrians on the road. It is therefore not only the individual patient who is at stake but essentially the entire community. In this case scenario, we describe the situation that arose when a patient with multi-infarct dementia wanted to go for a drive and his son and grandson tried to convince him that he could no longer drive. What went wrong in the caregivers/patient interaction is presented. The futility of arguing with patients who have dementia is highlighted as well as the suspiciousness it may generate. Alternate actions that can be useful to avoid/avert the situation from escalating and having a catastrophic ending are discussed. Testing/evaluating patients with dementia for fitness to drive is also reviewed and a list of select resources is included

    Prospective Longitudinal Study of the Pregnancy DNA Methylome: The US Pregnancy, Race, Environment, Genes (PREG) Study

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    Purpose The goal of the Pregnancy, Race, Environment, Genes study was to understand how social and environmental determinants of health (SEDH), pregnancy-specific environments (PSE) and biological processes influence the timing of birth and account for the racial disparity in preterm birth. The study followed a racially diverse longitudinal cohort throughout pregnancy and included repeated measures of PSE and DNA methylation (DNAm) over the course of gestation and up to 1 year into the postpartum period. Participants All women were between 18 and 40 years of age with singleton pregnancies and no diagnosis of diabetes or indication of assisted reproductive technology. Both mother and father had to self-identify as either African-American (AA) or European-American (EA). Maternal peripheral blood samples along with self-report questionnaires measuring SEDH and PSE factors were collected at four pregnancy visits, and umbilical cord blood was obtained at birth. A subset of participants returned for two additional postpartum visits, during which additional questionnaires and maternal blood samples were collected. The pregnancy and postpartum extension included n=240 (AA=126; EA=114) and n=104 (AA=50; EA=54), respectively. Findings to date One hundred seventy-seven women (AA=89, EA=88) met full inclusion criteria out of a total of 240 who were initially enrolled. Of the 63 participants who met exclusion criteria after enrolment, 44 (69.8%) were associated with a medical reason. Mean gestational age at birth was significantly shorter for the AA participants by 5.1 days (M=272.5 (SD=10.5) days vs M=277.6 (SD=8.3)). Future plans Future studies will focus on identifying key environmental factors that influence DNAm change across pregnancy and account for racial differences in preterm birth

    Patients with Dementia Are Easily Distracted

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    Mild cognitive impairment (MCI) is the middle ground between normal, age-appropriate memory impairment, and dementia. Whereas patients with MCI are able to cope with the memory deficit, those with dementia are not: Their memory impairment and other cognitive deficits are of sufficient magnitude to interfere with the patients’ ability to cope independently with daily activities. In both MCI and dementia, there is evidence of declining cognitive functions from a previously higher level of functioning. In both the conditions, there is also an evidence of dysfunction in one or more cognitive domains. There are two subtypes of MCI depending on whether memory is predominantly affected: amnestic type and nonamnestic/behavioral type. Not all patients with MCI transition to dementia, some recover. In this case scenario, we present a 68-year-old man with MCI who lives with his wife. They are getting ready to host dinner. His wife asks him to vacuum the dining room while she runs an urgent errand. We describe how this simple task vacuuming a room ended in a catastrophe with the patient spending the night in jail and his wife hospitalized. We discuss what went wrong in the patient/wife interaction and how the catastrophic ending could have been avoided

    Visual Hallucinations and Paranoid Delusions

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    Visual well-formed hallucinations, fluctuations in the level of cognition, and alertness and extrapyramidal signs are core features of dementia with Lewy bodies. Some patients realize that what they are seeing or hearing are just hallucinations and learn to accept them. Others, however experience these hallucinations as quite real and cannot be dissuaded from the firm belief that they are. In fact, efforts to dissuade them often serve only to confirm the often associated paranoid delusions and this may lead to a catastrophic ending. Hence, it is best not to contradict the patient. Instead, attempts should be made to distract the patient and change the focus of her or his attention. In this case scenario, we present a 68-year-old man who has been diagnosed with dementia with Lewy bodies. He lives with his daughter. He has visual hallucinations and paranoid delusions that worsen at night: He thinks there are people outside the house plotting to kill him. We discuss what went wrong in the patient/caregiver interaction and how the catastrophic ending could have been avoided or averted

    Repetitive Questioning II

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    Repetitive questioning is a major problem for caregivers, particularly taxing if they are unable to recognize and understand the reasons why their loved one keeps asking the same question over and over again. Caregivers may be tempted to believe that the patient does not even try to remember the answer given or is just getting obnoxious. This is incorrect. Repetitive questioning is due to the underlying disease: The patient’s short term memory is impaired and he is unable to register, encode, retain and retrieve the answer. If he is concerned about a particular topic, he will keep asking the same question over and over again. To the patient each time she asks the question, it is as if she asked it for the first time. Just answering repetitive questioning by providing repeatedly the same answer is not sufficient. Caregivers should try to identify the underlying cause for this repetitive questioning. In an earlier case study, the patient was concerned about her and her family’s safety and kept asking whether the doors are locked. In this present case study, the patient does not know how to handle the awkward situation he finds himself in. He just does not know what to do. He is not able to adjust to the new unexpected situation. So he repeatedly wants to reassure himself that he is not intruding by asking the same question over and over again. We discuss how the patient’s son-in-law could have avoided this situation and averted the catastrophic ending
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