Spacecraft design project: High latitude communications satellite

The spacecraft design project was part of AE-4871, Advanced Spacecraft Design. The project was intended to provide experience in the design of all major components of a satellite. Each member of the class was given primary responsibility for a subsystem or design support function. Support was requested from the Naval Research Laboratory to augment the Naval Postgraduate School faculty. Analysis and design of each subsystem was done to the extent possible within the constraints of an eleven week quarter and the design facilities (hardware and software) available. The project team chose to evaluate the design of a high latitude communications satellite as representative of the design issues and tradeoffs necessary for a wide range of satellites. The High-Latitude Communications Satellite (HILACS) will provide a continuous UHF communications link between stations located north of the region covered by geosynchronous communications satellites, i.e., the area above approximately 60 N latitude. HILACS will also provide a communications link to stations below 60 N via a relay Net Control Station (NCS), which is located with access to both the HILACS and geosynchronous communications satellites. The communications payload will operate only for that portion of the orbit necessary to provide specified coverage

WZW Commutants, Lattices, and Level 1 Partition Functions

A natural first step in the classification of all `physical' modular invariant partition functions \sum N_{LR}\,\c_L\,\C_R lies in understanding the commutant of the modular matrices $S$ and $T$. We begin this paper extending the work of Bauer and Itzykson on the commutant from the $SU(N)$ case they consider to the case where the underlying algebra is any semi-simple Lie algebra (and the levels are arbitrary). We then use this analysis to show that the partition functions associated with even self-dual lattices span the commutant. This proves that the lattice method due to Roberts and Terao, and Warner, will succeed in generating all partition functions. We then make some general remarks concerning certain properties of the coefficient matrices $N_{LR}$, and use those to explicitly find all level 1 partition functions corresponding to the algebras $B_n$, $C_n$, $D_n$, and the 5 exceptionals. Previously, only those associated to $A_n$ seemed to be generally known.Comment: 26 page

Dissecting a complex chemical stress: chemogenomic profiling of plant hydrolysates.

The efficient production of biofuels from cellulosic feedstocks will require the efficient fermentation of the sugars in hydrolyzed plant material. Unfortunately, plant hydrolysates also contain many compounds that inhibit microbial growth and fermentation. We used DNA-barcoded mutant libraries to identify genes that are important for hydrolysate tolerance in both Zymomonas mobilis (44 genes) and Saccharomyces cerevisiae (99 genes). Overexpression of a Z. mobilis tolerance gene of unknown function (ZMO1875) improved its specific ethanol productivity 2.4-fold in the presence of miscanthus hydrolysate. However, a mixture of 37 hydrolysate-derived inhibitors was not sufficient to explain the fitness profile of plant hydrolysate. To deconstruct the fitness profile of hydrolysate, we profiled the 37 inhibitors against a library of Z. mobilis mutants and we modeled fitness in hydrolysate as a mixture of fitness in its components. By examining outliers in this model, we identified methylglyoxal as a previously unknown component of hydrolysate. Our work provides a general strategy to dissect how microbes respond to a complex chemical stress and should enable further engineering of hydrolysate tolerance

The W_N minimal model classification

We first rigourously establish, for any N, that the toroidal modular invariant partition functions for the (not necessarily unitary) W_N(p,q) minimal models biject onto a well-defined subset of those of the SU(N)xSU(N) Wess-Zumino-Witten theories at level (p-N,q-N). This permits considerable simplifications to the proof of the Cappelli-Itzykson-Zuber classification of Virasoro minimal models. More important, we obtain from this the complete classification of all modular invariants for the W_3(p,q) minimal models. All should be realised by rational conformal field theories. Previously, only those for the unitary models, i.e. W_3(p,p+1), were classified. For all N our correspondence yields for free an extensive list of W_N(p,q) modular invariants. The W_3 modular invariants, like the Virasoro minimal models, all factorise into SU(3) modular invariants, but this fails in general for larger N. We also classify the SU(3)xSU(3) modular invariants, and find there a new infinite series of exceptionals.Comment: 25 page

The Multimorbidity Cluster Analysis Tool: Identifying Combinations and Permutations of Multiple Chronic Diseases Using a Record-Level Computational Analysis

Introduction: Multimorbidity, or the co-occurrence of multiple chronic health conditions within an individual, is an increasingly dominant presence and burden in modern health care systems.  To fully capture its complexity, further research is needed to uncover the patterns and consequences of these co-occurring health states.  As such, the Multimorbidity Cluster Analysis Tool and the accompanying Multimorbidity Cluster Analysis Toolkit have been created to allow researchers to identify distinct clusters that exist within a sample of participants or patients living with multimorbidity. Development: The Tool and Toolkit were developed at Western University in London, Ontario, Canada.  This open-access computational program (JAVA code and executable file) was developed and tested to support an analysis of thousands of individual records and up to 100 disease diagnoses or categories. Application: The computational program can be adapted to the methodological elements of a research project, including type of data, type of chronic disease reporting, measurement of multimorbidity, sample size and research setting.  The computational program will identify all existing, and mutually exclusive, combinations and permutations within the dataset.  An application of this computational program is provided as an example, in which more than 75,000 individual records and 20 chronic disease categories resulted in the detection of 10,411 unique combinations and 24,647 unique permutations among female and male patients. Discussion: The Tool and Toolkit are now available for use by researchers interested in exploring the complexities of multimorbidity.  Its careful use, and the comparison between results, will be valuable additions to the nuanced understanding of multimorbidity.

Perfil de los factores de riesgo asociados a la aparición de la primera infección intrahospitalaria en pacientes con quemaduras de segundo y tercer grado atendidos en el pabellón de Quemados de la Unidad de Servicios de Salud U. S. S. Simón Bolívar desde 1 de Enero hasta 31 de Julio del año 2018

102 páginasEn los pacientes con quemaduras existen diversos factores de riesgo, que favorecen la aparición de infecciones intrahospitalarias, una complicación frecuente debido a la condición fisiológica provocada por la lesión. Actualmente esto representa un serio problema de salud pública, el cual conlleva aumento significativo en la morbimortalidad y costos en salud. Se realiza un análisis descriptivo, retrospectivo y univariado que tiene como fin caracterizar los factores de riesgo asociados a la aparición de la primera de infección intrahospitalaria en pacientes con quemaduras de segundo y tercer grado en la Unidad de Servicios de Salud U.S.S. Simón Bolívar desde el 1 de enero hasta el 31 de julio del año 2018. En primer lugar, se seleccionó la población de estudio mediante criterios de inclusión y exclusión previamente establecidos, permitiendo así la caracterización de la población objeto. Posterior a esto se desarrolló un formulario para la recolección de información suministrada por las historias clínicas del pabellón de quemaduras en la U.S.S. Simón Bolívar, luego se procede analizar los datos encontrados, mediante frecuencias para variables cualitativas y prueba shapiro wilk para establecer la normalidad de las variables cuantitativas. Dentro de los factores de riesgo encontrados en el presente estudio asociados a la aparición de IAAS en los pacientes quemados son: ser remitido de otra institución, pertenecer al grupo de adultez, sufrir quemadura por llama o electricidad, presentar quemadura grado II superficial y profunda, demoras en el primer acto quirúrgico, modulación inadecuada de la respuesta inmune y fisiológica de los pacientes con quemaduras, presentar dos o mas segmentos comprometidos por la quemadura, y estancia hospitalaria prolongada.In patients with burns there are several risk factors that favor the appearance of nosocomial infections, a frequent complication due to the physiological condition caused by the injury. Currently, this represents a serious public health problem, which entails a significant increase in morbidity and mortality and health costs. A descriptive, retrospective and univariate analysis is carried out with the purpose of characterizing the risk factors associated with the appearance of the first intrahospital infection in patients with second and third degree burns in the U.S.S. Simón Bolívar from January 1 to July 31 of the year 2018. First, the study population was selected through previously established inclusion and exclusion criteria, thus allowing the characterization of the target population. Among the risk factors associated with IAAS were: Be remitted after 24 hours, time of the first surgical act, burned body segments, depth of burn, unmodulated inflammatory response, microbiology of the hospital and nutritional status of the patient.Incluye bibliografíaPregradoMédico(a) Cirujan

Association of thyroid hormone therapy with quality of life and thyroid-related symptoms in patients with subclinical hypothyroidism: a systematic review and meta-analysis

Importance: The benefit of thyroid hormone therapy for subclinical hypothyroidism is uncertain. New evidence from recent large randomized clinical trials warrants an update of previous meta-analyses. Objective: To conduct a meta-analysis of the association of thyroid hormone therapy with quality of life and thyroid-related symptoms in adults with subclinical hypothyroidism. Data Sources: PubMed, EMBASE, ClinicalTrials.gov, Web of Science, Cochrane Library, CENTRAL, Emcare, and Academic Search Premier from inception until July 4, 2018. Study Selection: Randomized clinical trials that compared thyroid hormone therapy with placebo or no therapy in nonpregnant adults with subclinical hypothyroidism were eligible. Two reviewers independently evaluated eligibility based on titles and abstracts of all retrieved studies. Studies not excluded in this first step were independently assessed for inclusion after full-text evaluation by 2 reviewers. Data Extraction and Synthesis: Two independent reviewers extracted data, assessed risk of bias (Cochrane risk-of-bias tool), and evaluated the quality of evidence (GRADE tool). For synthesis, differences in clinical scores were transformed (eg, quality of life) into standardized mean differences (SMDs; positive values indicate benefit of thyroid hormone therapy; 0.2, 0.5, and 0.8 correspond to small, moderate, and large effects, respectively). Random-effects models for meta-analyses were applied. Main Outcomes and Measures: General quality of life and thyroid-related symptoms after a minimum follow-up of 3 months. Results: Overall, 21 of 3088 initially identified publications met the inclusion criteria, with 2192 adults randomized. After treatment (range, 3-18 months), thyroid hormone therapy was associated with lowering the mean thyrotropin value into the normal reference range compared with placebo (range, 0.5-3.7 mIU/L vs 4.6 to 14.7 mIU/L) but was not associated with benefit regarding general quality of life (n = 796; SMD, −0.11; 95% CI, −0.25 to 0.03; I2=66.7%) or thyroid-related symptoms (n = 858; SMD, 0.01; 95% CI, −0.12 to 0.14; I2=0.0%). Overall, risk of bias was low and the quality of evidence assessed with the GRADE tool was judged moderate to high. Conclusions and Relevance: Among nonpregnant adults with subclinical hypothyroidism, the use of thyroid hormone therapy was not associated with improvements in general quality of life or thyroid-related symptoms. These findings do not support the routine use of thyroid hormone therapy in adults with subclinical hypothyroidism

Corporate sustainability reporting index and baseline data for the cruise industry

Sustainability policies and corporate reports demonstrate the impacts cruise companies acknowledge as their responsibility, and the actions put in place to address them. This paper develops a corporate social responsibility index based on the Global Reporting Initiative, with industry specific additions including labor and human rights, health and safety, and environmental and economic aspects. Companies disclose more management than performance data, which is typical of early stages of development. Companies disclosing less information focus on soft indicators which are easy to mimic and demonstrate posturing. Items disclosed tend to be marginal to the core of the business, have a positive economic impact or pre-empt sector regulation. Reports echo the voice of the corporations and not the demands of stakeholders. Institutional isomorphism has not influenced a homogenization in reporting, with only the largest firms reporting at this stage

A Monolithically-Integrated μGC Chemical Sensor System

Gas chromatography (GC) is used for organic and inorganic gas detection with a range of applications including screening for chemical warfare agents (CWA), breath analysis for diagnostics or law enforcement purposes, and air pollutants/indoor air quality monitoring of homes and commercial buildings. A field-portable, light weight, low power, rapid response, micro-gas chromatography (μGC) system is essential for such applications. We describe the design, fabrication and packaging of μGC on monolithically-integrated Si dies, comprised of a preconcentrator (PC), μGC column, detector and coatings for each of these components. An important feature of our system is that the same mechanical micro resonator design is used for the PC and detector. We demonstrate system performance by detecting four different CWA simulants within 2 min. We present theoretical analyses for cost/power comparisons of monolithic versus hybrid μGC systems. We discuss thermal isolation in monolithic systems to improve overall performance. Our monolithically-integrated μGC, relative to its hybrid cousin, will afford equal or slightly lower cost, a footprint that is 1/2 to 1/3 the size and an improved resolution of 4 to 25%

Free surface flows emerging from beneath a semi-infinite plate with constant vorticity

The free surface flow past a semi-infinite horizontal plate in a finite-depth fluid is considered. It is assumed that the fluid is incompressible and inviscid and that the flow approaches a uniform shear flow downstream. Exact relations are derived using conservation of mass and momentum for the case where the downstream free surface is flat. The complete nonlinear problem is solved numerically using a boundary integral method and these waveless solutions are shown to exist only when the height of the plate above the bottom is greater than the height of the uniform shear flow. Interesting results are found for various values of the constant vorticity. Solutions with downstream surface waves are also considered, and nonlinear results of this type are compared with linear results found previously. These solutions can be used to model the flow near the stern of a (two-dimensional) ship