849 resultados para Longitudinal field study


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Recent mathematics education reform efforts call for the instantiation of mathematics classroom environments where students have opportunities to reason and construct their understandings as part of a community of learners. Despite some successes, traditional models of instruction still dominate the educational landscape. This limited success can be attributed, in part, to an underdeveloped understanding of the roles teachers must enact to successfully organize and participate in collaborative classroom practices. Towards this end, an in-depth longitudinal case study of a collaborative high school mathematics classroom was undertaken guided by the following two questions: What roles do these collaborative practices require of teacher and students? How does the community’s capacity to engage in collaborative practices develop over time? The analyses produced two conceptual models: one of the teacher’s role, along with specific instructional strategies the teacher used to organize a collaborative learning environment, and the second of the process by which the class’s capacity to participate in collaborative inquiry practices developed over time.

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Fall season fertilization is a widely recommended practice for turfgrass. Fertilizer applied in the fall, however, may be subject to substantial leaching losses. A field study was conducted in Connecticut to determine the timing effects of fall fertilization on nitrate N (NO3-N) leaching, turf color, shoot density, and root mass of a 90% Kentucky bluegrass (Poa pratensis L.), 10% creeping red fescue (Festuca rubra L.) lawn. Treatments consisted of the date of fall fertilization: 15 September, 15 October, 15 November, 15 December, or control which received no fall fertilizer. Percolate water was collected weekly with soil monolith lysimeters. Mean log10 NO3-N concentrations in percolate were higher for fall fertilized treatments than for the control. Mean NO3-N mass collected in percolate water was linearly related to the date of fertilizer application, with higher NO3-N loss for later application dates. Applying fall fertilizer improved turf color and density but there were no differences in color or density among applications made between 15 October and 15 December. These findings suggest that the current recommendation of applying N in mid- to late November in southern New England may not be compatible with water quality goals.

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Knee osteoarthritis (OA) is the most prevalent form of arthritis in the US, affecting approximately 37% of adults. Approximately 300,000 total knee arthroplasty (TKA) procedures take place in the United States each year. Total knee arthroplasty is an elective procedure available to patients as an irreversible treatment after failure of previous medical treatments. Some patients sacrifice quality of life and endure many years of pain before making the decision to undergo total knee replacement. In making their decision, it is therefore imperative for patients to understand the procedure, risks and surgical outcomes to create realistic expectations and increase outcome satisfaction. ^ From 2004-2007, 236 OA patients who underwent TKA participated in the PEAKS (Patient Expectations About Knee Surgery) study, an observational longitudinal cohort study, completed baseline and 6 month follow-up questionnaires after the surgery. We performed a secondary data analysis of the PEAKS study to: (1) determine the specific presurgical patient characteristics associated with patients’ presurgical expectations of time to functional recovery; and (2) determine the association between presurgical expectations of time to functional recovery and postsurgical patient capabilities (6 months after TKA). We utilized the WOMAC to measure knee pain and function, the SF-36 to measure health-related quality of life, and the DASS and MOS-SSS to measure psychosocial quality of life variables. Expectation and capability measures were generated from panel of experts. A list of 10 activities was used for this analysis to measure functional expectations and postoperative functional capabilities. ^ The final cohort consisted of 236 individuals, was predominately White with 154 women and 82 men. The mean age was 65 years. Patients were optimistic about their time to functional recovery. Expectation time of being able to perform the list activities per patient had a median of less than 3 months. Patients who expected to be able to perform the functional activities by 3 months had better knee function, less pain and better overall health-related quality of life. Despite expectation differences, all patients showed significant improvement 6 months after surgery. Participant expectation of time to functional recovery was not an independent predictor of capability to perform functional activities at 6 months. Better presurgical patient characteristics were, however, associated with a higher likelihood of being able to perform all activities at 6 months. ^ This study gave us initial insight on the relationship between presurgical patient characteristics and their expectations of functional recovery after total knee replacement. Future studies clarifying the relationship between patient presurgical characteristics and postsurgical functional capabilities are needed.^

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The Long Term Acute Care Hospitals (LTACH), which serve medically complex patients, have grown tremendously in recent years, by expanding the number of Medicare patient admissions and thus increasing Medicare expenditures (Stark 2004). In an attempt to mitigate the rapid growth of the LTACHs and reduce related Medicare expenditures, Congress enacted Section 114 of P.L. 110-173 (§114) of the Medicare, Medicaid and SCHIP Extension Act (MMSEA) in December 29, 2007 to regulate the LTCAHs industry. MMSEA increased the medical necessity reviews for Medicare admissions, imposed a moratorium on new LTCAHs, and allowed the Centers for Medicare and Medicaid Services (CMS) to recoup Medicare overpayments for unnecessary admissions. ^ This study examines whether MMSEA impacted LTACH admissions, operating margins and efficiency. These objectives were analyzed by comparing LTACH data for 2008 (post MMSEA) and data for 2006-2007 (pre-MMSEA). Secondary data were utilized from the American Hospital Association (AHA) database and the American Hospital Directory (AHD).^ This is a longitudinal retrospective study with a total sample of 55 LTACHs, selected from 396 LTACHs facilities that were fully operational during the study period of 2006-2008. The results of the research found no statistically significant change in total Medicare admissions; instead there was a small but not statistically significant reduction of 5% in Medicare admissions for 2008 in comparison to those for 2006. A statistically significant decrease in mean operating margins was confirmed between the years 2006 and 2008. The LTACHs' Technical Efficiency (TE), as computed by Data Envelopment Analysis (DEA), showed significant decrease in efficiency over the same period. Thirteen of the 55 LTACHs in the sample (24%) in 2006 were calculated as “efficient” utilizing the DEA analysis. This dropped to 13% (7/55) in 2008. Longitudinally, the decrease in efficiency using the DEA extension technique (Malmquist Index or MI) indicated a deterioration of 10% in efficiency over the same period. Interestingly, however, when the sample was stratified into high efficient versus low efficient subgroups (approximately 25% in each group), a comparison of the MIs suggested a significant improvement in Efficiency Change (EC) for the least efficient (MI 0.92022) and reduction in efficiency for the most efficient LTACHs (MI = 1.38761) over same period. While a reduction in efficiency for the most efficient is unexpected, it is not particularly surprising, since efficiency measure can vary over time. An improvement in efficiency, however, for the least efficient should be expected as those LTACHs begin to manage expenses (and controllable resources) more carefully to offset the payment/reimbursement pressures on their margins from MMSEA.^

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Ascertaining the family health history (FHH) may provide insight into genetic and environmental susceptibilities specific to a variety of chronic diseases, including type II diabetes mellitus. However, discussion of FHH during patient-provider encounters has been limited and uncharacterized. A longitudinal, observational study was conducted in order to compare the content of FHH topics in a convenience sample of 37 patients, 13 new and 24 established. Each patient had an average of three follow-up encounters involving 6 staff physicians at the Audie L. Murphy Memorial Veterans Hospital (VHA) in San Antonio, TX from 2003 to 2005. A total of 131 encounters were analyzed in this study. The average age of the selected population was 68 years and included 35 males and two females. Transcriptions of encounters were obtained, coded and analyzed, in NVIVO 8. Of the 131 total encounters transcribed among the 37 patients, only 24 encounters (18.3%) included discussion of FHH. Additionally, the relationship between FHH discussion and discussion of self-care management (SCM) topics were assessed. In this study, providers were more likely to initiate discussion on family health history among new patients in the first encounter (ORnew = 8.55, 95% CI: 1.49–52.90). The discussion of FHH occurred sporadically in established patients throughout the longitudinal study with no apparent pattern. Provider-initiated FHH discussion most frequently had satisfactory level(s) of discussion while patient-initiated FHH discussion most frequently had minimal level(s) of discussion. FHH discussion most oftentimes involved topics of cancer and cardiovascular disease among primary-degree familial relationships. Overall, family health histories are largely, an underutilized tool in personalized preventive care.^

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To address concerns expressed about the possible effect of drilling mud discharges on shallow, low-energy estuarine ecosystems, a 12 month study was designed to detect alterations in water quality and sediment geochemistry. Each drilling mud used in the study and sediments from the study site were analyzed in the laboratory for chemical and physical characteristics. Potential water quality impacts were simulated by the EPA-COE elutriation test procedure. Mud toxicity was measured by acute and chronic bioassays with Mysidopsis bahia, Mercenaria mercenaria, and Nereis virens.^ For the field study, a relatively pristine, shallow (1.2 m) estuary (Christmas Bay, TX) without any drilling activity for the last 30 years was chosen for the study site. After a three month baseline study, three stations were selected. Station 1 was an external control. At each treatment station (2, 3), mesocosms were constructed to enclose a 3.5 m$\sp3$ water column. Each treatment station included an internal control site also. Each in situ mesocosm, except the controls, was successively dosed at a mesocosm-specific dose (1:100; 1:1,000; or 1:10,000 v/v) with 4 field collected drilling muds (spud, nondispersed, lightly-treated, and heavily-treated lignosulfonate) in sequential order over 1.5 months. Twenty-four hours after each dose, water exchange was allowed until the next treatment. Station 3 was destroyed by a winter storm. After the last treatment, the enclosures were removed and the remaining sites monitored for 6 months. One additional site was similarly dosed (1:100 v/v) with clean dredged sediment from Christmas Bay for comparison between dredged sediments and drilling muds.^ Results of the analysis of the water samples and field measurements showed that water quality was impacted during the discharges, primarily at the highest dose (1:100 v/v), but that elevated levels of C, Cr (T,F), Cr$\sp{+3}$ (T, F), N, Pb, and Zn returned to ambient levels before the end of the 24 hour exposure period or immediately after water exchange was allowed (Al, Ba(T), Chlorophyll ABC, SS, %T). Barium, from the barite, was used as a geochemical tracer in the sediments to confirm estimated doses by mass balance calculations. Barium reached a maximum of 166x background levels at the high dose mesocosm. Barium levels returned to ambient or only slightly elevated levels at the end of the 6 month monitoring period due to sediment deposition, resuspension, and bioturbation. QA/QC results using blind samples consisting of lab standards and spiked samples for both water and sediment matrices were within acceptable coefficients of variation.^ In order to avoid impacts on water quality and sediment geochemistry in a shallow estuarine ecosystem, this study concluded that a minimal dilution of 1:1,000 (v/v) would be required in addition to existing regulatory constraints. ^

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We conducted a six-week investigation of the sea ice inorganic carbon system during the winter-spring transition in the Canadian Arctic Archipelago. Samples for the determination of sea ice geochemistry were collected in conjunction with physical and biological parameters as part of the 2010 Arctic-ICE (Arctic - Ice-Covered Ecosystem in a Rapidly Changing Environment) program, a sea ice-based process study in Resolute Passage, Nunavut. The goal of Arctic-ICE was to determine the physical-biological processes controlling the timing of primary production in Arctic landfast sea ice and to better understand the influence of these processes on the drawdown and release of climatically active gases. The field study was conducted from 1 May to 21 June, 2010.

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Este trabajo sintetiza los resultados de un estudio de campo realizado en la Organización Territorial del Movimiento de Trabajadores Desocupados Aníbal Verón del Barrio Malvinas de la ciudad de La Plata, entre el mes de Marzo del año 2003 (momento en el cual la Organización Territorial comienza sus actividades en el barrio y se incorpora, paulatinamente, al Movimiento de Trabajadores Desocupados Aníbal Verón) y los primeros meses del año 2005, cuando esta Organización conforma, junto a otras, el Frente Popular Darío Santillán. Los principales temas aquí desarrollados están relacionados, en principio, con la novedosa forma de participación político-comunitaria que insertó esta Organización Territorial en un barrio como Malvinas donde predominaban, desde hacía más de veinte años, formas de participación político-comunitarias de tipo clientelar. Otro de los temas aquí abordados está relacionado con los vínculos existentes entre la Organización Territorial y el Movimiento Regional. En esta trama vincular, se observó un desfasaje entre los criterios y acuerdos propuestos por el movimiento y las prácticas político-comunitarias llevadas adelante por la organización y los vecinos del barrio. Por último, en esta investigación también son centrales los distintos tipos de actores que interpretaban al movimiento de diferente manera. Aquí se observaron diversas formas de actuar, participar y comprometerse. En aquel momento, esto me llevó a proponer el armado de una tipología de participación de la que se desprende que la participación de los integrantes de la Organización Territorial del MTD Aníbal Verón del Barrio Malvinas, entre el año 2003 y 2005 era directa, inestable y complementaria. Lo que hacía que se fuera modificando con el propio devenir de la organización en movimiento. Es un trabajo más bien empírico y se nutrió por un lado, de datos obtenidos de entrevistas y observaciones realizadas para dos proyectos de extensión en los cuales participé y por otro, del trabajo de campo realizado entre el mes de Junio del año 2003 y Marzo del año 2005. El trabajo de campo constó de observaciones participantes y no participantes y, de entrevistas a los integrantes de la organización territorial. Entre el mes de octubre del año 2003 y el mes de enero del año 2004 realicé veinte entrevistas en profundidad. Para su realización se tomaron cuotas por sexo y edad hasta agotar información

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Este trabajo sintetiza los resultados de un estudio de campo realizado en la Organización Territorial del Movimiento de Trabajadores Desocupados Aníbal Verón del Barrio Malvinas de la ciudad de La Plata, entre el mes de Marzo del año 2003 (momento en el cual la Organización Territorial comienza sus actividades en el barrio y se incorpora, paulatinamente, al Movimiento de Trabajadores Desocupados Aníbal Verón) y los primeros meses del año 2005, cuando esta Organización conforma, junto a otras, el Frente Popular Darío Santillán. Los principales temas aquí desarrollados están relacionados, en principio, con la novedosa forma de participación político-comunitaria que insertó esta Organización Territorial en un barrio como Malvinas donde predominaban, desde hacía más de veinte años, formas de participación político-comunitarias de tipo clientelar. Otro de los temas aquí abordados está relacionado con los vínculos existentes entre la Organización Territorial y el Movimiento Regional. En esta trama vincular, se observó un desfasaje entre los criterios y acuerdos propuestos por el movimiento y las prácticas político-comunitarias llevadas adelante por la organización y los vecinos del barrio. Por último, en esta investigación también son centrales los distintos tipos de actores que interpretaban al movimiento de diferente manera. Aquí se observaron diversas formas de actuar, participar y comprometerse. En aquel momento, esto me llevó a proponer el armado de una tipología de participación de la que se desprende que la participación de los integrantes de la Organización Territorial del MTD Aníbal Verón del Barrio Malvinas, entre el año 2003 y 2005 era directa, inestable y complementaria. Lo que hacía que se fuera modificando con el propio devenir de la organización en movimiento. Es un trabajo más bien empírico y se nutrió por un lado, de datos obtenidos de entrevistas y observaciones realizadas para dos proyectos de extensión en los cuales participé y por otro, del trabajo de campo realizado entre el mes de Junio del año 2003 y Marzo del año 2005. El trabajo de campo constó de observaciones participantes y no participantes y, de entrevistas a los integrantes de la organización territorial. Entre el mes de octubre del año 2003 y el mes de enero del año 2004 realicé veinte entrevistas en profundidad. Para su realización se tomaron cuotas por sexo y edad hasta agotar información

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Este trabajo sintetiza los resultados de un estudio de campo realizado en la Organización Territorial del Movimiento de Trabajadores Desocupados Aníbal Verón del Barrio Malvinas de la ciudad de La Plata, entre el mes de Marzo del año 2003 (momento en el cual la Organización Territorial comienza sus actividades en el barrio y se incorpora, paulatinamente, al Movimiento de Trabajadores Desocupados Aníbal Verón) y los primeros meses del año 2005, cuando esta Organización conforma, junto a otras, el Frente Popular Darío Santillán. Los principales temas aquí desarrollados están relacionados, en principio, con la novedosa forma de participación político-comunitaria que insertó esta Organización Territorial en un barrio como Malvinas donde predominaban, desde hacía más de veinte años, formas de participación político-comunitarias de tipo clientelar. Otro de los temas aquí abordados está relacionado con los vínculos existentes entre la Organización Territorial y el Movimiento Regional. En esta trama vincular, se observó un desfasaje entre los criterios y acuerdos propuestos por el movimiento y las prácticas político-comunitarias llevadas adelante por la organización y los vecinos del barrio. Por último, en esta investigación también son centrales los distintos tipos de actores que interpretaban al movimiento de diferente manera. Aquí se observaron diversas formas de actuar, participar y comprometerse. En aquel momento, esto me llevó a proponer el armado de una tipología de participación de la que se desprende que la participación de los integrantes de la Organización Territorial del MTD Aníbal Verón del Barrio Malvinas, entre el año 2003 y 2005 era directa, inestable y complementaria. Lo que hacía que se fuera modificando con el propio devenir de la organización en movimiento. Es un trabajo más bien empírico y se nutrió por un lado, de datos obtenidos de entrevistas y observaciones realizadas para dos proyectos de extensión en los cuales participé y por otro, del trabajo de campo realizado entre el mes de Junio del año 2003 y Marzo del año 2005. El trabajo de campo constó de observaciones participantes y no participantes y, de entrevistas a los integrantes de la organización territorial. Entre el mes de octubre del año 2003 y el mes de enero del año 2004 realicé veinte entrevistas en profundidad. Para su realización se tomaron cuotas por sexo y edad hasta agotar información

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This field study was performed to obtain a defensible value for the surface reflectivity (albedo) of Juniper shrublands that could be used by Brigitta Ammann to quantitatively assess the role of Juniper shrublands in surface energy balance feedbacks to climate after the last glaciation. Measurements were carried out over a Juniper shrubland at mount Niederhorn, Switzerland (North of the Lake of Thun) during summer 2009 over a Juniper shrubland that was considered to present the most representative surface cover to estimate albedo for a modeling exercise that addresses biotic responses to the rapid warming around 14.685 ka BP at Gerzensee (Central Europe). For a detailed description of this data set see "Further details:"

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A field study was conducted in Santala Bay with weekly samplings during February and March 2000. Ice thickness was 20-28 cm, snow cover 0-1 cm. The under-ice water column was stratified with a cold (-0.3 - 0.2°C) and less saline (S = 2.1-4.9) interface layer. Concentrations of particulate organic carbon (0.5-5.8 mg POC/l) and algal pigments (0.3-18.2 µg chlorophyll a/l) were higher in the ice than in the water (0.2-0.5 mg POC/l, 1.6-7.1 µg chlorophyll a/l) and peaked mostly in the bottom part of the ice. The thin ice and almost lacking snow cover had favoured an early ice-algal and phytoplankton bloom. The diversity of metazoans was low, with six species in the ice and eight species in the under-ice water. The rotifer Synchaeta cf. littoralis dominated both in ice and water, with maximum abundances of 230 individuals/l in the bottom part of the ice. Rotifer eggs were also observed in the ice. Baltic sea ice seems to be a suitable habitat for rotifers. Nauplii and copepodids of the calanoid Acartia longiremis in the under-ice water showed some herbivorous feeding (<0.1-0.23 ng gut pigment/individual), but analysis of fatty acids, fatty alcohols and biomarker ratios indicated a more omnivorous/carnivorous diet. Despite low temperatures, this copepod showed growth and development below the ice, doubling in numbers (mainly CI, CII) from 118 to 230 individuals m during the third week of March.

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We present results from a field study of inorganic carbon (C) acquisition by Ross Sea phytoplankton during Phaeocystis-dominated early season blooms. Isotope disequilibrium experiments revealed that HCO3? was the primary inorganic C source for photosynthesis in all phytoplankton assemblages. From these experiments, we also derived relative enhancement factors for HCO3?/CO2 interconversion as a measure of extracellular carbonic anhydrase activity (eCA). The enhancement factors ranged from 1.0 (no apparent eCA activity) to 6.4, with an overall mean of 2.9. Additional eCA measurements, made using membrane inlet mass spectrometry (MIMS), yielded activities ranging from 2.4 to 6.9 U/[?g chl a] (mean 4.1). Measurements of short-term C-fixation parameters revealed saturation kinetics with respect to external inorganic carbon, with a mean half-saturation constant for inorganic carbon uptake (K1/2) of ~380 ?M. Comparison of our early springtime results with published data from late-season Ross Sea assemblages showed that neither HCO3? utilization nor eCA activity was significantly correlated to ambient CO2 levels or phytoplankton taxonomic composition. We did, however, observe a strong negative relationship between surface water pCO2 and short-term 14C-fixation rates for the early season survey. Direct incubation experiments showed no statistically significant effects of pCO2 (10 to 80 Pa) on relative HCO3? utilization or eCA activity. Our results provide insight into the seasonal regulation of C uptake by Ross Sea phytoplankton across a range of pCO2 and phytoplankton taxonomic composition.

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Environmental cues can affect food decisions. There is growing evidence that environmental cues influence how much one consumes. This article demonstrates that environmental cues can similarly impact the healthiness of consumers’ food choices. Two field studies examined this effect with consumers of vending machine foods who were exposed to different posters. In field study 1, consumers with a health-evoking nature poster compared to a pleasure-evoking fun fair poster or no poster in their visual sight were more likely to opt for healthy snacks. Consumers were also more likely to buy healthy snacks when primed by an activity poster than when exposed to the fun fair poster. In field study 2, this consumer pattern recurred with a poster of skinny Giacometti sculptures. Overall, the results extend the mainly laboratory-based evidence by demonstrating the health-relevant impact of environmental cues on food decisions in the field. Results are discussed in light of priming literature emphasizing the relevance of preexisting associations, mental concepts and goals.