The use of computer-assisted experiments in the canine to support the development of a mathematical model for the hepatic removal of indocyanine green dye under normal and reduced hepatic blood flow conditions

Sixteen mongrel dogs were tested for hepatic removal of indocyanine green (ICG) dye in normal animals and animals with portal-caval shunts. Characteristics of blood ICG clearance and bile ICG accumulation were studied. Response of the mathematical model is similar to the response from the studies of normal animals when programmed with initial parameters taken from the animal studies. A data-handling system was developed for the acquisition of the experimental data. Cardiac output decreased two-fold (p \u3c 0.01) following a portal-caval shunt. Dye decay rate in the plasma decreased (p \u3c 0.05) which resulted in an increase in area under the blood concentration curve and time to zero concentration in the shunted animals. Mean bile flow was reduced two-fold (p \u3c 0.05) while the area under the ascending bile curve increased (p \u3c 0.05) in the shunted animals. A method in which to measure the volume of the bile canalicular space has been discovered by analysis of the descending portion of the bile dye curve. Effects of methoxyfluorane-nitrous oxide anesthetic on the hepatic system appear to be minimal with respect to dye clearance as seen by relatively small differences between the animal data and the mathematical model

Changes in pulmonary function and hepatic flow associated with a surgically induced porto-caval shunt

http://www.worldcat.org/oclc/703490

The Influence of Multiple Fluorination on the Ring Opening of [2.2.2]Propellane

Effect of electronegative substituents on ring opening of [2.2.2]propellane was examined by quantum chemical calculations at CASSCF and CASPT2 level of theory. Comparison of the results with those obtained with MR-AQCC calculations indicated that calculations beyond CASSCF level were needed for reliable description of the process. Calculations show a strong effect of fluorination on the central bond elongation energy profile, with the effect being most pronounced for the perfluoro derivative. Moreover, for rearrangement of the most of multiply fluorinated derivatives, including perfluoro[2.2.2]propellane, CASPT2 calculations predict a single minimum potential energy well, which hampers rearrangement to significantly more stable fluorinated 1,4-dimethylenecyclohexane analogues. This observation is in harmony with high stability of synthetically available stable heavily fluorinated derivatives which, in contrast to the parent [2.2.2]propellane, do not rearrange to the thermodynamically most stable fluorinated 1,4-dimethylene-cyclohexane isomer. This work is licensed under a Creative Commons Attribution 4.0 International License

Commercially Hosted Government Payloads: Lessons from Recent Programs

In a commercially hosted operational mode, a scientific instrument or operational device is attached to a spacecraft but operates independently from the spacecraft s primary mission. Despite the expected benefits of this arrangement, there are few examples of hosted payload programs actually being executed by government organizations. The lack of hosted payload programs is largely driven by programmatic challenges, both real and perceived, rather than by technical challenges. Partly for these reasons, NASA has not sponsored a hosted payload program, in spite of the benefits and visible community interest in doing so. In the interest of increasing the use of hosted payloads across the space community, this paper seeks to alleviate concerns about hosted payloads by identifying these programmatic challenges and presenting ways in which they can be avoided or mitigated. Despite the challenges, several recent hosted payload programs have been successfully completed or are currently in progress. This paper presents an assessment of these programs, with a focus on acquisition, costs, schedules, risks, and other programmatic aspects. The hosted payloads included in this study are the Federal Aviation Administration's Wide Area Augmentation System (WAAS) payloads, United States Coast Guard's Automatic Identification System (AIS) demonstration payload, Department of Defense's IP Router In Space (IRIS) demonstration payload, the United States Air Force's Commercially Hosted Infrared Payload (CHIRP), and the Australian Defence Force's Ultra High Frequency (UHF) payload. General descriptions of each of these programs are presented along with issues that have been encountered and lessons learned from those experiences. A set of recommended approaches for future hosted payload programs is presented, with a focus on addressing risks or potential problem areas through smart and flexible contracting up front. This set of lessons and recommendations is broadly applicable to future hosted payload programs, whether they are technology demonstrations, communications systems, or operational sensors. Additionally, we present a basic cost model for commercial access to space for hosted payloads as a function of payload mas

Ambigedad causal, pr cticas de recursos humanos de alto compromiso y resultados empresariales

El enfoque basado en los recursos (EBR) (resource-based view RBV) sugiere que las empresas conseguir n y mantendr n en el tiempo una posici¢n de ventaja competitiva solamente si sus recursos son inimitables. Es por ello, que la protecci¢n frente a la imitaci¢n se convierte en un aspecto clave para las empresas de hoy en d¡a. Tradicionalmente, se ha reconocido en la literatura que existe una relaci¢n positiva entre el nivel de protecci¢n de las competencias y la existencia de ambigedad causal. Sin embargo, algunos estudios recientes apuntan, en contra de este supuesto, que la existencia de dicha ambigedad en el seno de las empresas impide la transferencia de competencias en el interior de las organizaciones, lo que dificulta la consecuci¢n de altos resultados. El primer objetivo de esta investigaci¢n es analizar ambas corrientes con el fin £ltimo de establecer cu l es la influencia neta que ejerce la ambigedad causal sobre los rendimientos corporativos. El segundo, analizar c¢mo las pr cticas de recursos humanos de alto compromiso o alta participaci¢n pueden contribuir a resolver este debate. Para ello, se propone un conjunto de hip¢tesis que ser n contrastadas en una muestra de 258 empresas manufactureras espa¤olas. The resource-based view (RBV) predicts that firms will achieve and sustain a position of competitive advantage over time only if their resources and capabilities are difficult to imitate. Traditionally, it has been recognised that causal ambiguity, by making it difficult for competitors to identify the capabilities on which a particular firm bases its competitive advantage, represents an effective protection mechanism helping the firm to obtain superior performance. Recently, researchers have unearthed evidence that the effects of causal ambiguity also could be extend to the interior of the firm itself, hampering the diffusion of its own capabilities among its managers. In this case, the existence of causal ambiguity will have a negative impact on firm performance. In this paper we study both effects using a sample of 258 Spanish manufacturing firms, and we show that causal ambiguity exerts a doubleedged influence on firm performance. On the positive side, in its effect on the firm?s competitors, and on the negative, in its effect on the firm?s managers, with this second effect being stronger.Ambigedad causal, imitaci¢n, transferencia de competencias, pr cticas de recursos humanos de alto compromiso. Causal ambiguity, imitation, transfer of competencies.

Computational Study of Electronic Influence of Guanidine Substitution on Diels-Alder Reactions of Heterocyclic Dienes

Quantum-chemical calculations of cycloaddition properties of cyclic heterodienes substituted with guanidine functionality were carried out. Molecular and electronic structures of series of dienes (pyrrole, furan, thiophene, isoindole and 1,3-butadiene) were calculated and reactivity order established on the basis of FMO theory. Transition state calculations of model [4+2] cycloaddition reaction with acetylene indicate that guanidine substitution influences reaction barriers in moderate extent (up to ~4 kcal mol–1). The substitution position plays an important role on the sign and magnitude of the effect and protonation of nitrogen possessing substituents increases reactivity of dienes. This work is licensed under a Creative Commons Attribution 4.0 International License

Adult insect personality in the wild-Calopteryx splendens as a model for field studies

Animal personality has received increasing interest and acknowledgment within ecological research over the past two decades. However, some areas are still poorly studied and need to be developed. For instance, field studies focused on invertebrates are currently highly underrepresented in the literature. More studies including a wider variety of traits measured and species tested are needed to improve our understanding of trait-correlation patterns and generalities. We studied nine behavioral traits, in the damselfly Calopteryx splendens, from an array of three experiments: (i) courtship, (ii) aggressiveness, and (iii) boldness, and calculated their repeatability. The behaviors were measured twice in two different contexts: (i) undisturbed territory and (ii) partially deteriorated territory. Traits related to courtship and boldness were all repeatable across the two contexts. Among aggressive behaviors, only one trait (number of hits) was repeatable. This work demonstrates, for the first time, the presence of within-population personality differences in an adult damselfly in the wild. We further propose C. splendens as a promising model species for testing personality in the wild under highly controlled environmental conditions

Predictors of Patient Activation Among Underserved Patients in a Nurse-managed Health Center: A Pilot Study

The concept of patient activation has gained traction as the term referring to patients who understand their role in the care process and have “the knowledge, skills and confidence” necessary to manage their illness over time (Hibbard & Mahoney, 2010). Improving health outcomes for vulnerable and underserved populations who bear a disproportionate burden of health disparities presents unique challenges for nurse practitioners who provide primary care in nurse-managed health centers. Evidence that activation improves patient self-management is prompting the search for theory-based self-management support interventions to activate patients for self-management, improve health outcomes, and sustain long-term gains. Yet, no previous studies investigated the relationship between Self-determination Theory (SDT; Deci & Ryan, 2000) and activation. The major purpose of this study, guided by the Triple Aim (Berwick, Nolan, & Whittington, 2008) and nested in the Chronic Care Model (Wagner et al., 2001), was to examine the degree to which two constructs– Autonomy Support and Autonomous Motivation– independently predicted Patient Activation, controlling for covariates. For this study, 130 nurse-managed health center patients completed an on-line 38-item survey onsite. The two independent measures were the 6-item Modified Health Care Climate Questionnaire (mHCCQ; Williams, McGregor, King, Nelson, & Glasgow, 2005; Cronbach’s alpha =0.89) and the 8-item adapted Treatment Self-Regulation Questionnaire (TSRQ; Williams, Freedman, & Deci, 1998; Cronbach’s alpha = 0.80). The Patient Activation Measure (PAM-13; Hibbard, Mahoney, Stock, & Tusler, 2005; Cronbach’s alpha = 0.89) was the dependent measure. Autonomy Support was the only significant predictor, explaining 19.1% of the variance in patient activation. Five of six autonomy support survey items regressed on activation were significant, illustrating autonomy supportive communication styles contributing to activation. These results suggest theory-based patient, provider, and system level interventions to enhance self-management in primary care and educational and professional development curricula. Future investigations should examine additional sources of autonomy support and different measurements of autonomous motivation to improve the predictive power of the model. Longitudinal analyses should be conducted to further understand the relationship between autonomy support and autonomous motivation with patient activation, based on the premise that patient activation will sustain behavior change