787 resultados para difference-in-differences


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The purpose of this study was to examine the effects of the use of technology on students’ mathematics achievement, particularly the Florida Comprehensive Assessment Test (FCAT) mathematics results. Eleven schools within the Miami-Dade County Public School System participated in a pilot program on the use of Geometers Sketchpad (GSP). Three of these schools were randomly selected for this study. Each school sent a teacher to a summer in-service training program on how to use GSP to teach geometry. In each school, the GSP class and a traditional geometry class taught by the same teacher were the study participants. Students’ mathematics FCAT results were examined to determine if the GSP produced any effects. Students’ scores were compared based on assignment to the control or experimental group as well as gender and SES. SES measurements were based on whether students qualified for free lunch. The findings of the study revealed a significant difference in the FCAT mathematics scores of students who were taught geometry using GSP compared to those who used the traditional method. No significant differences existed between the FCAT mathematics scores of the students based on SES. Similarly, no significant differences existed between the FCAT scores based on gender. In conclusion, the use of technology (particularly GSP) is likely to boost students’ FCAT mathematics test scores. The findings also show that the use of GSP may be able to close known gender and SES related achievement gaps. The results of this study promote policy changes in the way geometry is taught to 10th grade students in Florida’s public schools.

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The purpose of this study was to examine job satisfaction of dietitians in South Florida and to identify significant differences in job satisfaction between dietitians working in traditional versus non-traditional settings. A job satisfaction questionnaire was developed, validated, and mailed to dietitians in Palm Beach, Broward, Dade, and Monroe counties. Out of 600 questionnaires mailed, 203 surveys were returned and 187 were valid and analyzed statistically. Seventy three percent of subjects practiced in traditional and 17% in non-traditional settings. Eighteen percent of 187 subjects surveyed reported feeling dissatisfied with their jobs and 59% reported feeling satisfied. There was no significant difference in satisfaction due to practice settings (traditional versus non-traditional). The subjects reported satisfaction with co-workers and supervisors. The two major areas where dissatisfaction was reported were compensation and professional recognition. The results showed that the majority of dietitians in South Florida are, in general, satisfied with their jobs. Although dietitians' salaries have increased by approximately 80% since 1982, compensation was still viewed as inadequate by 48% of the subjects, given dietitians' education, skills and experience. Because legislation to approve reimbursement of medical nutrition therapy is pending, increase in dietitians' knowledge of reimbursement issues is recommended. Dietitians must also promote assertively their valuable contribution to wellness, health, and the treatment of disease.

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Objectives To evaluate the change in masticatory efficiency and quality of life of patients treated with mandibular Kennedy class I removable partial dentures (RPDs) and maxillary complete dentures at the Department of Dentistry of the Federal University of Rio Grande do Norte. Materials and methods A total of 33 Kennedy class I patients were rehabilitated with maxillary complete dentures, and mandibular RPDs were selected for this non-randomized prospective intervention study. The patients had a mean age of 59.1 years. Masticatory efficiency was evaluated by colorimetric assay using fuchsin capsules. The measurements were conducted at baseline and 2 and 6 months after prosthesis insertion. Quality of life was evaluated using the Oral Health Impact Profile (OHIP-14) at baseline and 6 months after denture insertion. The Kolmogorov-Smirnov normality test was applied. Masticatory efficiency was evaluated by repeated measures ANOVA. Oral health-related quality of life was compared using the paired t test. Results There was no statistically significant difference in masticatory efficiency after denture insertion (p = 0.101). Significant differences were found (p = 0.010) for oral health-related quality of life. A significant improvement in psychological discomfort (p < 0.01) and psychological disability (p < 0.01) was observed. Mean difference value (95 % confidence interval) was 6.8 (3.8 to 9.7) points, reflecting a low impact of oral health on quality of life, considering the 0–56 range of variation of the OHIP-14 and a Cohen’s d of 1.13. Conclusion According to the results of the present study, rehabilitation with Kennedy class I RPDs and complete dentures did not influence masticatory efficiency but improved oral health-related quality of life. Clinical relevance The association between the patient’s quality of life and the masticatory efficiency is important for treatment predictability.

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OBJECTIVE: The aim of this study was to compare the immunohistochemical expression of nuclear factor κB (NF-κB), matrix metalloproteinase 9 (MMP-9), and CD105 in odontogenic keratocysts (OKCs), dentigerous cysts (DCs), and radicular cysts (RCs). STUDY DESIGN: Twenty cases of OKCs, 20 DCs, and 20 RCs were analyzed. A labeling index (LI), which expresses the percentage of NF-κB-stained nuclei, was calculated for the analysis of NF-κB expression. Expression of MMP-9 in the epithelium and in the capsule of each lesion was scored as 0 (<10% stained cells), 1 (10%-50% stained cells), or 2 (>50% stained cells). In addition, MMP-9 immunostaining was analyzed in endothelial cells of vessels with a conspicuous lumen. The angiogenic index was determined based on the number of anti-CD105 antibody-stained microvessels. RESULTS: In the epithelial component, the NF-κB LI was higher in OKCs than in DCs and RCs (P < .001). Analysis of MMP-9 expression in the epithelial component showed a predominance of score 2 in OKCs (90%), DCs (70%), and RCs (65%; P = .159). Evaluation of the NF-κB LI according to the expression of MMP-9 in the epithelial lining revealed no significant difference between lesions (P = .282). In the fibrous capsule, the highest percentage of MMP-9-stained cells (score 2) was observed in OKCs (P = .100). Analysis of the expression of MMP-9 in the vessels of odontogenic cysts showed a predominance of score 2 in OKCs (80%) and RCs (50%) and of score 1 in DCs (75%; P = .002). Mean microvessel count was high in RCs (16.9), followed by DCs (12.1) and OKCs (10.0; P = .163). No significant difference in microvessel count according to the expression of MMP-9 was observed between groups (P = .689). CONCLUSIONS: The results suggest that the more aggressive biologic behavior of OKCs is related to the higher expression of MMP-9 and NF-κB in those lesions. The differences in the biologic behavior of the lesions studied do not seem to be associated with the angiogenic index.

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OBJECTIVE: The aim was to analyze the expression of E-cadherin and beta-catenin in ameloblastomas and tooth germs to determine their roles in cell differentiation processes and invasiveness compared with odontogenesis. STUDY DESIGN: Twenty-one ameloblastoma cases (16 solid and 5 unicystic tumors) and 5 tooth germs were submitted to the immunohistochemical detection of E-cadherin and beta-catenin. Immunoreactivity was evaluated using descriptive and semiquantitative analysis, investigating the location and intensity of staining. The Fisher exact test was performed, and P values of <.05 were considered to indicate statistical significance. RESULTS: There was no statistically significant difference in the expression of E-cadherin and beta-catenin between solid and unicystic ameloblastomas (P = .59; P = .63; respectively). The same was found when comparing solid and unicystic ameloblastomas with the tooth germs for both E-cadherin (P = .53; P = .44; respectively) and beta-catenin (P = .12; P = .16; respectively). Nuclear staining of beta-catenin was observed in only 4 cases (3 solid and 1 unicystic tumor). CONCLUSION: The results showed no differences in the expression of E-cadherin or beta-catenin between tooth germs and solid and unicystic ameloblastomas. The expression of these molecules seems mainly to be related to the process of cell differentiation.

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The expression of integrins alpha2beta1, alpha3beta1, and alpha5beta1 in 30 ameloblastomas (20 solid and 10 unicystic tumors), 12 adenomatoid odontogenic tumors (AOTs), and 5 human tooth germs in different stages of odontogenesis was analyzed. The distribution, location, pattern, and intensity of immunohistochemical expression were evaluated. Intensity was analyzed using scores (0 = absence, 1 = weak staining, and 2 = strong staining). No difference in the immunoexpression of the integrins was observed between solid and unicystic ameloblastomas. When these two ameloblastoma types were pooled into a single group, the following significant differences were found: immunoexpression of integrin alpha2beta1 was stronger in ameloblastomas than in AOTs and tooth germs, and the expression of integrin alpha5beta1 was stronger in ameloblastomas than in AOTs. The lack of detection of integrin alpha3beta1 in tooth germs and its detection in the odontogenic tumors studied suggest that this integrin might be used as a marker of neoplastic transformation in odontogenic tissues.

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The expression of integrins alpha2beta1, alpha3beta1, and alpha5beta1 in 30 ameloblastomas (20 solid and 10 unicystic tumors), 12 adenomatoid odontogenic tumors (AOTs), and 5 human tooth germs in different stages of odontogenesis was analyzed. The distribution, location, pattern, and intensity of immunohistochemical expression were evaluated. Intensity was analyzed using scores (0 = absence, 1 = weak staining, and 2 = strong staining). No difference in the immunoexpression of the integrins was observed between solid and unicystic ameloblastomas. When these two ameloblastoma types were pooled into a single group, the following significant differences were found: immunoexpression of integrin alpha2beta1 was stronger in ameloblastomas than in AOTs and tooth germs, and the expression of integrin alpha5beta1 was stronger in ameloblastomas than in AOTs. The lack of detection of integrin alpha3beta1 in tooth germs and its detection in the odontogenic tumors studied suggest that this integrin might be used as a marker of neoplastic transformation in odontogenic tissues.

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Objectives: to identify factors associated with admission after suicide spectrum behaviors. Methods: Patient's characteristics, the nature of their suicidal behavior, admission rates between centres, and factors associated with admission have been examined in suicide spectrum presentations to emergency departments in three Spanish cities. Results: Intent of the suicidal behavior had the greatest impact on hospitalization. Older age, living alone, self-harm method not involving drug overdose, previous history of suicide spectrum behaviors and psychiatric diagnosis of schizophrenia, mood or personality disorder were independently associated with being admitted. There was a three-fold between-centre difference in the rate of hospitalization. Conclusions: widespread differences in the rate of hospitalization were primarily accounted for by characteristics of the individual patients and their suicidal behavior.

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BACKGROUND: In order to reduce fatal self-poisoning legislation was introduced in the UK in 1998 to restrict pack sizes of paracetamol sold in pharmacies (maximum 32 tablets) and non-pharmacy outlets (maximum 16 tablets), and in Ireland in 2001, but with smaller maximum pack sizes (24 and 12 tablets). Our aim was to determine whether this resulted in smaller overdoses of paracetamol in Ireland compared with the UK. METHODS: We used data on general hospital presentations for non-fatal self-harm for 2002-2007 from the Multicentre Study of Self-harm in England (six hospitals), and from the National Registry of Deliberate Self-harm in Ireland. We compared sizes of overdoses of paracetamol in the two settings. RESULTS: There were clear peaks in numbers of non-fatal overdoses, associated with maximum pack sizes of paracetamol in pharmacy and non-pharmacy outlets in both England and Ireland. Significantly more pack equivalents (based on maximum non-pharmacy pack sizes) were used in overdoses in Ireland (mean 2.63, 95% CI 2.57-2.69) compared with England (2.07, 95% CI 2.03-2.10). The overall size of overdoses did not differ significantly between England (median 22, interquartile range (IQR) 15-32) and Ireland (median 24, IQR 12-36). CONCLUSIONS: The difference in paracetamol pack size legislation between England and Ireland does not appear to have resulted in a major difference in sizes of overdoses. This is because more pack equivalents are taken in overdoses in Ireland, possibly reflecting differing enforcement of sales advice. Differences in access to clinical services may also be relevant.

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Dancers of all forms often engage in aesthetic yet challenging movements. Their training, choreography, and performances require strength, stamina, flexibility, grace, passion, and emotion. Ballet and Bharatanatyam (an Indian classical dance form) dancers utilize two movements in each of their dance forms that are similar—a half-sitting pose and a full-sitting pose, both requiring external rotation of the legs and bending at the knee joints. The purpose of this study was to examine and compare the biomechanics of joint reaction forces and knee angles in both styles of dance for these particular poses. The study included nine female ballet dancers and seven female Bharatanatyam dancers. Hamstring and gastrocnemius flexibility were measured for each dancer. Knee angles, vertical peak forces, and moments were determined for dancers at the lowest point of their bending positions. Mann-Whitney U tests found significant differences in hamstring flexibility, right gastrocnemius flexibility, and knee angles for the full-sitting poses between ballet and Bharatanatyam dancers. No significant difference was found in the vertical peak forces as a ratio to total body weight and moments between the two styles of dance. Further research can be done to more directly assess a difference in injury risk between the ballet and Bharatanatyam dancers.

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Aim: To investigate the characteristics, development and determinants of toothwear among Irish schoolchildren. Methods: A cross-sectional (examination at 16-years-old) and longitudinal (examinations at 5-,12-,14-years) study were conducted. Two indices were used to measure toothwear, children/parents completed a demographic profile and questionnaire on oral hygiene and dietary practices, health, and lifestyle in both studies. Saliva was collected from consenting 16-year-olds. The explanatory variables for the cross-sectional and longitudinal study were derived from children/parents responses. Differences in salivary profiles were determined for subsets; the protein concentration was determined with Bradford protein assay and protein carbonyl concentration (a protein oxidation marker) was determined spectrophotometrically. Gel-electrophoresis and mass spectrometry determined proteins and ion chromatography inorganic ions. Statistical significance was accepted at p<0.05. Results: At 16-years-old the prevalence of toothwear with dentine visible was 44%. No difference in salivary flow rates existed. In unstimulated saliva a higher mean, protein carbonyl (p<0.0001) and total calcium concentration (p<0.002) existed for the group with moderate toothwear. In stimulated saliva the moderate toothwear group had a lower mean protein concentration(p<0.0001). The 2-DE protein spots prepared for a sub-group differed between those with toothwear and without. Mass spectrometry, identified one of the different proteins as IgA. For 16-year-olds, the self-reported factors indicated that brushing after breakfast was associated with lower toothwear scores(p<0.03). Nail-biting, being asthmatic or reporting a dry mouth were associated with higher toothwear scores(all p<0.05). Eating an apple daily or less was associated with less toothwear(p<0.002). In the longitudinal study toothwear into dentine at age five or 12-years was associated with more toothwear at age 14(all p<0.05). Discussion: The results illustrate the multifactorial aetiology of toothwear. The biochemical and physical correlates of saliva with toothwear requires further research. Conclusion: The impact of previous toothwear, salivary, dietary and personal factors on toothwear in the early permanent dentition is demonstrated.

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The purpose of this study is to examine the effects of agglomeration economies on the productivity of manufacturing local units in Ireland. Four types of agglomeration economies are considered in this study. These are internal economies of scale, localization economies, related variety and urbanization economies. This study makes a number of contributions to the literature. Firstly, this is the first study to conduct an investigation of the effects of agglomeration economies on the productivity of manufacturing local units operating in Ireland. Secondly, this study distinguishes between indigenous and foreign-owned local units which is important given the dual nature of the Irish economy (Krugman, 1997). Thirdly, in addition to considering the effects of agglomeration economies, this study examines the impact of spurious agglomeration on the productivity of foreign-owned local units. Using data from the Census of Industrial Local Units and a series of IV GMM estimators to control for endogeneity, the results of the analysis conducted in Chapter 6 reveal that there are differences in the effects of agglomeration economies on the productivity of indigenous and foreign-owned local units. In Chapter 7 the Census of Industrial Local Units is supplemented by additional data sources and more in-depth measures are generated to capture the features of each of the external agglomeration economies considered in this analysis. There is some evidence to suggest that the availability of local inputs has a negative and significant impact on productivity. The NACE based measures of related variety reveal that the availability of local inputs and knowledge spillovers for related sectors have a negative and significant impact on productivity. There is clear evidence to suggest that urbanization economies are important for increasing the productivity of indigenous local units. The findings reveal that a 1% increase in population density in the NUTS 3 region leads to an increase in the productivity of indigenous local units of approximately 0.07% to 0.08%. The results also reveal that there is a significant difference in the effects of agglomeration economies on the productivity of low-tech and medium/high-tech indigenous local units. The more in-depth measures of agglomeration economies used in Chapter 7 are also used in Chapter 8. A series of IV GMM regressions are estimated in order to identify the impact of agglomeration economies and spurious agglomeration on the productivity of foreign-owned local units operating in Ireland. There is some evidence found to suggest that the availability of a pool of skilled labour has a positive and significant on productivity of foreign-owned local units. There is also evidence to suggest that localization knowledge spillovers have a negative impact on the productivity of foreign-owned local units. There is strong evidence to suggest that the availability of local inputs has a negative impact on the productivity. The negative impact is not confined to the NACE 4-digit sector but also extends into related sectors as determined by Porter’s (2003) cluster classification. The cluster based skills measure of related variety has a positive and significant impact on the productivity of foreign-owned local units. Similar to Chapter 7, there is clear evidence to suggest that urbanization economies are important for increasing the productivity of foreign-owned local units. Both the summary measure and each of the more in-depth measures of agglomeration economies have a positive and significant impact on productivity. Spurious agglomeration has a positive and significant impact on the productivity of foreign-owned local units. The results indicate that the more foreign-owned local units of the same nationality in the country the greater the levels of productivity for the local unit. From a policy perspective, urbanization economies are clearly important for increasing the productivity of both indigenous and foreign-owned local units. Furthermore, the availability of a pool of skilled labour appears to be important for increasing the productivity of foreign-owned local units. Another policy implication that arises from these results relates to the differences observed between indigenous local units and foreign-owned local units and also between low-tech and medium/high-tech indigenous local units. These findings indicate that ‘one-size-fits-all’ type policies are not appropriate for increasing the productivity of local units operating in Ireland. Policies should be tailored to the needs of either indigenous or foreign-owned local units and also to specific sectors. This positive finding for own country spurious agglomeration is important from a policy perspective and is one that IDA Ireland should take on board.

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Intensive Care Units (ICUs) account for over 10 percent of all US hospital beds, have over 4.4 million patient admissions yearly, approximately 360,000 deaths, and account for close to 30% of acute care hospital costs. The need for critical care services has increased due to an aging population and medical advances that extend life. The result is efforts to improve patient outcomes, optimize financial performance, and implement models of ICU care that enhance quality of care and reduce health care costs. This retrospective chart review study examined the dose effect of APN Intensivists in a surgical intensive care unit (SICU) on differences in patient outcomes, healthcare charges, SICU length of stay, charges for APN intensivist services, and frequency of APNs special initiatives when the SICU was staffed by differing levels of APN Intensivist staffing over four time periods (T1-T4) between 2009 and 2011. The sample consisted of 816 randomly selected (204 per T1-T4) patient chart data. Study findings indicated reported ventilator associated pneumonia (VAP) rates, ventilator days, catheter days and catheter associated urinary tract infection (CAUTI) rates increased at T4 (when there was the lowest number of APN Intensivists), and there was increased pressure ulcer incidence in first two quarters of T4. There was no statistically significant difference in post-surgical glycemic control (M = 142.84, SD= 40.00), t (223) = 1.40, p = .17, and no statistically significant difference in the SICU length of stay among the time-periods (M= 3.27, SD = 3.32), t (202) = 1.02, p= .31. Charges for APN services increased over the 4 time periods from $11,268 at T1 to $51,727 at T4 when a system to capture APN billing was put into place. The number of new APN initiatives declined in T4 as the number of APN Intensivists declined. Study results suggest a dose effect of APN Intensivists on important patient health outcomes and on the number of APNs initiatives to prevent health complications in the SICU.

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English has been taught as a core and compulsory subject in China for decades. Recently, the demand for English in China has increased dramatically. China now has the world’s largest English-learning population. The traditional English-teaching method cannot continue to be the only approach because it merely focuses on reading, grammar and translation, which cannot meet English learners and users’ needs (i.e., communicative competence and skills in speaking and writing). This study was conducted to investigate if the Picture-Word Inductive Model (PWIM), a new pedagogical method using pictures and inductive thinking, would benefit English learners in China in terms of potential higher output in speaking and writing. With the gauge of Cognitive Load Theory (CLT), specifically, its redundancy effect, I investigated whether processing words and a picture concurrently would present a cognitive overload for English learners in China. I conducted a mixed methods research study. A quasi-experiment (pretest, intervention for seven weeks, and posttest) was conducted using 234 students in four groups in Lianyungang, China (58 fourth graders and 57 seventh graders as an experimental group with PWIM and 59 fourth graders and 60 seventh graders as a control group with the traditional method). No significant difference in the effects of PWIM was found on vocabulary acquisition based on grade levels. Observations, questionnaires with open-ended questions, and interviews were deployed to answer the three remaining research questions. A few students felt cognitively overloaded when they encountered too many writing samples, too many new words at one time, repeated words, mismatches between words and pictures, and so on. Many students listed and exemplified numerous strengths of PWIM, but a few mentioned weaknesses of PWIM. The students expressed the idea that PWIM had a positive effect on their English teaching. As integrated inferences, qualitative findings were used to explain the quantitative results that there were no significant differences of the effects of the PWIM between the experimental and control groups in both grade levels, from four contextual aspects: time constraints on PWIM implementation, teachers’ resistance, how to use PWIM and PWIM implemented in a classroom over 55 students.

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Mercury concentrations ([Hg]) in Arctic food fish often exceed guidelines for human subsistence consumption. Previous research on two food fish species, Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush), indicates that anadromous fish have lower [Hg] than nonanadromous fish, but there have been no intraregional comparisons. Also, no comparisons of [Hg] among anadromous (sea-run), resident (marine access but do not migrate), and landlocked (no marine access) life history types of Arctic char and lake trout have been published. Using intraregional data from 10 lakes in the West Kitikmeot area of Nunavut, Canada, we found that [Hg] varied significantly among species and life history types. Differences among species-life history types were best explained by age-at-size and C:N ratios (indicator of lipid); [Hg] was significantly and negatively related to both. At a standardized fork length of 500 mm, lake trout had significantly higher [Hg] (mean 0.17 µg/g wet wt) than Arctic char (0.09 µg/g). Anadromous and resident Arctic char had significantly lower [Hg] (each 0.04 µg/g) than landlocked Arctic char (0.19 µg/g). Anadromous lake trout had significantly lower [Hg] (0.12 µg/g) than resident lake trout (0.18 µg/g), but no significant difference in [Hg] was seen between landlocked lake trout (0.21 µg/g) and other life history types. Our results are relevant to human health assessments and consumption guidance and will inform models of Hg accumulation in Arctic fish.