5 resultados para Time-resolved methods

em DigitalCommons@The Texas Medical Center


Relevância:

90.00% 90.00%

Publicador:

Resumo:

This paper defines and compares several models for describing excess influenza pneumonia mortality in Houston. First, the methodology used by the Center for Disease Control is examined and several variations of this methodology are studied. All of the models examined emphasize the difficulty of omitting epidemic weeks.^ In an attempt to find a better method of describing expected and epidemic mortality, time series methods are examined. Grouping in four-week periods, truncating the data series to adjust epidemic periods, and seasonally-adjusting the series y(,t), by:^ (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)^ is the best method examined. This new series w(,t) is stationary and a moving average model MA(1) gives a good fit for forecasting influenza and pneumonia mortality in Houston.^ Influenza morbidity, other causes of death, sex, race, age, climate variables, environmental factors, and school absenteeism are all examined in terms of their relationship to influenza and pneumonia mortality. Both influenza morbidity and ischemic heart disease mortality show a very high relationship that remains when seasonal trends are removed from the data. However, when jointly modeling the three series it is obvious that the simple time series MA(1) model of truncated, seasonally-adjusted four-week data gives a better forecast.^

Relevância:

80.00% 80.00%

Publicador:

Resumo:

We detect internal water molecules in a membrane-embedded receptor-transducer complex and demonstrate water structure changes during formation of the signaling state. Time-resolved FTIR spectroscopy reveals stimulus-induced repositioning of one or more structurally active water molecules to a significantly more hydrophobic environment in the signaling state of the sensory rhodopsin II (SRII)-transducer (HtrII) complex. These waters, distinct from bound water molecules within the SRII receptor, appear to be in the middle of the transmembrane interface region near the Tyr199(SRII)-Asn74(HtrII) hydrogen bond. We conclude that water potentially plays an important role in the SRII --> HtrII signal transfer mechanism in the membrane's hydrophobic core.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The interaction between sensory rhodopsin II (SRII) and its transducer HtrII was studied by the time-resolved laser-induced transient grating method using the D75N mutant of SRII, which exhibits minimal visible light absorption changes during its photocycle, but mediates normal phototaxis responses. Flash-induced transient absorption spectra of transducer-free D75N and D75N joined to 120 amino-acid residues of the N-terminal part of the SRII transducer protein HtrII (DeltaHtrII) showed only one spectrally distinct K-like intermediate in their photocycles, but the transient grating method resolved four intermediates (K(1)-K(4)) distinct in their volumes. D75N bound to HtrII exhibited one additional slower kinetic species, which persists after complete recovery of the initial state as assessed by absorption changes in the UV-visible region. The kinetics indicate a conformationally changed form of the transducer portion (designated Tr*), which persists after the photoreceptor returns to the unphotolyzed state. The largest conformational change in the DeltaHtrII portion was found to cause a DeltaHtrII-dependent increase in volume rising in 8 micros in the K(4) state and a drastic decrease in the diffusion coefficient (D) of K(4) relatively to those of the unphotolyzed state and Tr*. The magnitude of the decrease in D indicates a large structural change, presumably in the solvent-exposed HAMP domain of DeltaHtrII, where rearrangement of interacting molecules in the solvent would substantially change friction between the protein and the solvent.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Purpose. The purpose of this study was to determine the perceptions of work engagement of Taiwanese nurses with 3 specific aims: (1) understand Taiwanese nurses' perceptions of work engagement; (2) explore the factors influencing work engagement, and (3) examine how work engagement impacts nursing care for patients. ^ Design. The study used an ethnographic approach with participant observation and semi-structured interviews with RNs. ^ Setting. The study was conducted in the highest and lowest nurse turnover medical surgical units at a regional teaching hospital in southwestern Taiwan. ^ Sample. Purposive sampling resulted in 28 formal interviews with RNs who provided direct patient care, had at least 3 months experience in nursing, and were full-time employees. ^ Methods. Descriptive data were collected through participant observation in each unit. Observations were made while attending meetings, continuing education sessions, and informal conversations with RNs. Field notes and audio recorded semi-structured interviews were analyzed using qualitative thematic analytic techniques. ^ Findings. Findings revealed perceptions of work engagement spanned four domains: patients ("wholehearted care"), work (positive attitude), self (fulfillment and happiness), and others (relationships with colleagues). Providing "wholehearted care" toward patients was the foundation of work engagement for nurses in Taiwan. Engaged nurses felt fulfilled, happy, and found "meaning" through the process of patient care. The study revealed five factors that influenced work engagement: personal, organizational, social, patient, and professional. The impact of work engagement on nurse and patient outcomes are confirmed. ^ Conclusions. Taiwanese nurses connect work engagement with patients, the job, oneself, and colleagues. "Wholehearted patient care" is the core manifestation of work engagement among these nurses. In contrast, studies in western business only focused on work attitudes. Losing interest and "heart" lead to work routines which can lead to individual unhappiness. Findings from this study validate the multiple factors contributing to work engagement of nurses. Job demands and resources can only partially explain what hinders work engagement. Work disengagement and burnout share some commonality but should be measured differently. An understanding of RNs' perceptions of work engagement may provide direction for strategies that improve work engagement leading to decreased RN turnover. ^

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Background: Once thought to be eradicated, pertussis is now making a steady comeback throughout Texas and the United States. Pertussis can have an effect on all demographics, but infants have the greatest health concern as they suffer the highest case-fatality rate. The objective of this study was to create and report a comprehensive summary of confirmed or probable pertussis cases in a Texas County during the 2008 through 2012 time period.^ Methods: A cross-sectional study design was used to show at risk populations in a Texas county using descriptive statistics of data from probable and confirmed pertussis cases in this Texas County from 2008-2012. Data was collected during routine pertussis investigations conducted by the local health department of this Texas County.^ Results: There was a sharp increase in pertussis cases seen in this county in 2012. Hispanics made up the majority of cases (74.9%) as compared to 12.8% of cases among Whites, 3.1% of cases among Blacks and 9.2% of cases among unknown/other. The population of Hispanics within this county was 58.9%. Almost a quarter of cases (24.2%) in this study were hospitalized. There was no difference identified in the proportion of male sources of exposure (48.9%) as compared to female (51.1%). Household contacts were the main sources of exposure: siblings (29.2%), fathers (14.5%), children (14.6%), and mothers (12.5%).^ Conclusion: Prevention intervention needs to be designed to target vulnerable populations and reduce the effect of this sometimes fatal disease. These results show pertussis proportionally has a greater effect on Hispanics. Additional research needs to be conducted on risk factors such as household crowding and immunization status among Hispanics to identify if ethnicity plays a role in risk of transmission of pertussis. The results were limited due to the large amount of missing data in vaccination history and identification of source of exposure.^