Improving Mathematics Problem Solving Through Written Explanations

In this action research study of two classrooms of 7th grade mathematics, I investigated how requiring written explanations of problem solving would affect students ability to problem solve, their ability to write good explanations, and how it would affect their attitudes toward mathematics and problem solving. I studied a regular 7th grade mathematics class and a lower ability 7th grade class to see if there would be any difference in what was gained by each group or any group. I discovered that there were no large gains made in the short time period of my action research. Some gains were made in ability to problem solve by my lower ability students over the 7 weeks that they did a weekly problem solving assignment. Some individual students felt that the writing had helped them in their problem solving because they needed to think and write each step. As a result of this research I plan to continue implementing writing in my classroom over the entire school year requiring a little more from students each time we problem solve and write.

Cooperative Learning Groups in the Middle School Mathematics Classroom

In this action research study of my classroom of 8th grade mathematics, I investigated the inclusion of cooperative learning groups. Data was collected to see how cooperative learning groups affected oral and written communication, math scores, and attitudes toward mathematics. On the one hand, I discovered that many students enjoyed the opportunity to work within a group. On the other hand, there continues to be a handful of students who would rather work alone. The benefits outweigh the demands. Overall, students benefitted from the inclusion of cooperative learning groups. Oral explanations of solutions and methods improved during the study. Written expression also improved over this time period. As a result of this research, I plan to continue with the incorporation of cooperative learning groups in the middle school math classroom.

Eastern temperate North Pacific offshore killer whales (Orcinus orca): Occurrence, movements, and insights into feeding ecology

Beginning in the late 1980s, large groups of previously unidentified killer whales (Orcinus orca) were sighted off the west coast of Vancouver Island and in the Queen Charlotte Islands, British Columbia. Scientists working in this region produced two killer whale photo-identification catalogues that included both transient (mammal-eating) whales and 65 individual whales that investigators believed represented a distinct killer whale community (Ford et al. 1992, Heise et al. 1993). It was thought that these killer whales maintained a generally offshore distribution and were provisionally termed “offshores”; a term that has since been used as a population identifier for the eastern temperate North Pacific offshore killer whale population. Then in September 1992, 75 unidentified whales entered the Strait of Juan de Fuca just south and east of Victoria, British Columbia (Walters et al. 1992). Although most of these whales had not been seen before, two were matched to killer whales in the Queen Charlotte photo-identification catalogue (Ford et al. 1992, Heise et al. 1993) and were thus listed as “offshore” killer whales. During a similar time period, other large groups of killer whales, previously unidentified, were also being sighted off Alaska and California (Dahlheim et al. 1997; Nancy Black and Alisa Schulman- Janiger, unpublished data, respectively).

Three Counties Saw the Majority of Nebraska’s Housing Growth 2007 – 2008

According to estimates released by the Bureau of the Census in August, 2009, Nebraska’s total housing stock increased by 5,529 units between July 1, 2007 and July 1, 2008, an increase of 0.7 percent for the year. This represented an estimated rate of growth in housing stock slightly below the state’s estimated rate of population growth, which was 0.8 percent for the same time period.

Community Life and Housing in Rural Nebraska: 2005 Nebraska Rural Poll Results

Many rural communities are experiencing population decline. However, rural residents have continued to show a strong attachment to their communities. How do rural Nebraskans feel about their community? Are they satisfied with the services provided? Do they own their home? What is the condition of their home? This report details 2,851 responses to the 2005 Nebraska Rural Poll, the tenth annual effort to understand rural Nebraskans’ perceptions. Respondents were asked a series of questions about their community and housing. Trends for some of these questions are examined by comparing data from the nine previous polls to this year’s results. For all questions, comparisons are made among different respondent subgroups, that is, comparisons by age, occupation, region, etc. Based on these analyses, some key findings emerged: Rural Nebraskans’ views of the change in their community are similar to those expressed last year. This year, 28 percent believe their community has changed for the better, compared to 26 percent last year. And, in 2005, only 20 percent think their community has changed for the worse, compared to 22 percent last year. The proportion of expected movers who plan to leave the state decreased this year. Last year, 56 percent of the persons planning to move from their community expected to leave the state. That proportion decreased to 47 percent this year. Rural Nebraskans living in or near the largest communities are more likely than persons living in or near the smaller communities to say their community has changed for the better. Thirty-nine percent of persons living in or near communities with populations of 10,000 or more believe their community has changed for the better during the past year, but only 15 percent of persons living in or near communities with less than 500 people share this opinion. The community services and amenities that rural Nebraskans are most dissatisfied with include: entertainment, retail shopping and restaurants. At least one-third of rural Nebraskans express dissatisfaction with these three services. They are most satisfied with parks and recreation, library services, basic medical care services, highways and bridges, and education (K - 12). At least one-half of rural Nebraskans are satisfied with the following items in their community: appearance of residential areas (66%), crime control (61%), maintenance of sidewalks and public areas (57%) and noise (54%). Rural Nebraskans generally have positive views about their community. Sixty percent agree that their community is an ideal place to live and 52 percent say their community has good business leaders. Rural Nebraskans have mixed opinions about the future of their community. Fortyfour percent agree that their community’s future looks bright, but 42 percent disagree with this statement. Fourteen percent have no opinion. Rural Nebraskans living in or near the larger communities are more likely than residents of the smaller communities to think their community’s future looks bright. Fifty-nine percent of persons living in or near communities with populations of 10,000 or more agree with this statement, compared to only 25 percent of residents living in or near communities with less than 500 people. Further, 61 percent of the residents of the smallest communities disagree with this statement, compared to only 28 percent of the residents of the largest communities. Over three-quarters of rural Nebraskans disagree that younger residents of their community tend to stay there after completing high school. Seventy-six percent disagree with this statement, 16 percent have no opinion and eight percent agree that younger residents stay after completing high school. When comparing responses by age, younger persons are more likely than older persons to agree that younger residents stay in their community after high school. Sixteen percent of persons age 19 to 29 agree with this statement, compared to only six percent of persons age 50 to 64. Younger persons are more likely than older persons to be planning to move from their community next year. Fifteen percent of persons between the ages of 19 and 29 are planning to move next year, compared to only two percent of persons age 65 and older. An additional 17 percent of the younger respondents indicate they are uncertain if they plan to move. Most rural Nebraskans own their home. Eighty-four percent of rural Nebraskans own their home. Older persons are more likely than younger persons to own their home. Eighty-eight percent of persons over the age of 50 own their home, compared to only 52 percent of persons age 19 to 29. Housing in rural Nebraska has an average age of 50 years. Twenty-four percent of residences were built before 1930. Another 24 percent were built between 1930 and 1959. Twenty-nine percent were built between 1960 and 1979 and the remaining 24 percent were built in 1980 or later. The housing stock in smaller communities is older than the housing located in larger communities. Over one-third (35%) of the residences in communities with less than 1,000 people were built before 1930. Only 12 percent of the homes in communities with populations of 10,000 or more were built in this time period. Most rural Nebraskans appear satisfied with their home. Only 24 percent say the current size of their home does not meet their needs. The same proportion (24%) say their home is in need of major repairs. Thirty-eight percent agree that their home needs a lot of routine maintenance, but 87 percent like the location (neighborhood) of their home. One-third of rural Nebraskans living in or near the smallest communities say their home is in need of major repairs. Only 19 percent of persons living in or near communities with populations of 5,000 or more are facing this problem. Home ownership is very important to most rural Nebraskans. Eighty-two percent believe it is very important to own their home. An additional 12 percent say it is somewhat important and six percent say it is not at all important. However, persons who do not currently own their home do not feel it is important for them to do so. Only 32 percent of renters say it is very important to own their home, compared to 91 percent of home owners. And, 35 percent of renters say it is not at all important to own their home.

Rural Nebraska: Looking Back at a Decade of Change and Progress: 2005 Nebraska Rural Poll Results

To commemorate the 10th anniversary of the Nebraska Rural Poll, rural Nebraskans were asked about changes they may have experienced during the past ten years. Where have they lived during the past decade? In what types of business activities have they been involved? Have they received any education or training during that time period? What has been their experience with the Internet? This report details 2,851 responses to the 2005 Nebraska Rural Poll, the tenth annual effort to understand rural Nebraskans’ perceptions. Respondents were asked a series of questions about changes they have experienced during the past ten years. For all questions, comparisons are made among different respondent subgroups, that is, comparisons by age, occupation, region, etc. Based on these analyses, some key findings emerged: One quarter of rural Nebraskans have lived somewhere other than their current community during the past ten years. Of those who have lived elsewhere, they have moved their primary residence an average of 2.2 times. Younger rural Nebraskans are more likely than older residents to have lived elsewhere during the past decade. Sixty-six percent of persons between the ages of 19 and 29 have lived in a different location, compared to only 12 percent of persons age 65 and older. Many rural Nebraskans who have lived in a different community during the past ten years have lived in another state. Forty-one percent of persons who have lived elsewhere during the past decade have lived in a different state. Forty-five percent have lived in a larger community (18% have lived in either Omaha or Lincoln and 27% have lived in or near a Nebraska community larger than their current one - other than Lincoln or Omaha). Thirty-six percent have lived in or near a Nebraska community smaller than their current one. Twenty percent of rural Nebraskans currently own a business. Thirteen percent started operating a business during the past ten years, 10 percent closed or stopped operating a business during this time period and four percent tried unsuccessfully to start a business. Persons living in or near the smallest communities are more likely than persons living in or near larger communities to currently own a business. Twenty-nine percent of persons living in or near communities with less than 500 people currently own a business, compared to 15 percent of persons living in or near communities with at least 10,000 persons. In general, rural Nebraskans have favorable opinions about self-employment but they also recognize the hardships and risks involved with this type of employment. Sixtyone percent agree that self-employment is desirable because they can be their own boss. Forty-four percent agree that self-employment provides a better quality of life than being an employee. However, 74 percent agree that self-employed individuals work longer hours than traditional employees and 70 percent agree that the cost of health insurance makes self-employment unappealing. Younger persons are more likely than older persons to agree that the cost of health insurance makes self-employment unappealing. Eighty percent of persons age 19 to 29 agree with that statement, compared to 55 percent of persons age 65 and older. One-half of rural Nebraskans have participated in formal education courses, workshops or other training activities during the past ten years. Sixty-nine percent of rural Nebraskans have Internet access either at home or at work. Sixty-six percent have acquired Internet access either at home or at work during the past ten years. An additional three percent had acquired access more than ten years ago. Persons with higher levels of income are more likely than persons with lower incomes to have acquired Internet access. Sixty-six percent of persons with household incomes of $60,000 or more have acquired Internet access at both home and work during the past ten years, compared to only 11 percent of persons with household incomes less than $20,000. Information searches and email are the most important reasons for having an Internet connection. Eighty-nine percent of rural Nebraskans with access to the Internet at either home or work say that information searches are an important or very important reason for having an Internet connection. Eighty-three percent say email is an important reason. In general, rural Nebraskans say their satisfaction with various features of their Internet connection has increased during the past ten years. Fifty-five percent of rural Nebraskans with an Internet connection at home say their satisfaction with the availability of service has increased during the past ten years and 50 percent report an increase in their satisfaction with the speed of their connection. Persons living in or near the larger communities are more likely than persons living in or near the smaller communities to say their satisfaction with the speed of their Internet connection has increased during the past ten years. Fifty-four percent of persons living in or near communities with populations of 5,000 or more say their satisfaction with the speed of their connection has increased over the past decade, compared to 43 percent of persons living in or near communities with less than 1,000 people.

Práticas integrativas e complementares no SUS: revisão integrativa

Pós-graduação em Saúde Coletiva - FMB

Levantamento de nematoides entomopatogênicos em áreas agrícolas e influência da temperatura e do substrato na sobrevivência, multiplicação e armazenamento

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Diagnostic of Silicon Carbide Surge Arresters using Leakage Current Measurement

Nowadays, the zinc oxide surge arresters (ZnO) are widely used in power systems, however, a large number of silicon carbide surge arresters (SiC) are still in service in the utilities. On the other hand, it is not possible to replace all SiC surge arresters in a short time period, being necessary to review the maintenance program taking into account the surge arresters that are more degraded. In this context, a research project was established between the University of Sao Paulo and the electrical utility CTEEP, aiming the investigation of its SiC surge arresters. This work shows that the leakage current measurement, a diagnostic method for the ZnO surge arresters, can provide useful information related to the condition of the SiC surge arresters. Analysis of the amplitude and distortion of the leakage current, also considering thermovision measurements, resulted in better evaluation of the SiC surge arresters.

A 30-year quantitative comparison of the bird community of a semideciduous forest remnant in the state of Sao Paulo

A 30-year quantitative comparison of the bird community of a semideciduous forest remnant in the state of Sao Paulo. Few studies have evaluated long-term changes in avian abundance in forest remnants. To compare both species richness and abundance of the bird community in a forest fragment located in the municipality of Galia, state of Sao Paulo, southeastern Brazil, we surveyed forest birds using transect counts. We compared our results with a survey conducted 30 years earlier at the same locality and further classified bird species according to their food habits to eventually predict fluctuations of specific abundance. Although species with population declines predominated in the community, all trophic categories had species which increased their abundances. Most species prone to move around remnants decreased in abundance. We suggest that, regarding specific abundances, trophic categories may be equally affected as a result of fragmentation processes and that the forest regeneration of this remnant may have led to the loss of edge species. Species that suffered from abundance loss during this time period may become locally extinct in the near future.

Effects of RegCM3 parameterizations on simulated rainy season over South America

The impacts of change in the Grell convective scheme and biosphere-atmosphere transfer scheme (BATS) in RegCM3 are described. Three numerical experiments (RegZhang, RegClaris and RegArain) are conducted to reduce the RegCM3-Grell rainfall underestimation over tropical South America. The simulation referred to as RegZhang follows modifications made by Zhang et al. (2008) in the BATS. The RegClaris combines the RegZhang BATS parameters with a reduction of water drainage at the bottom of the subsoil layer in the regions covered by the tropical rain forest and a shorter convective time period for the Grell scheme. The RegArain considers this same modification in the Grell scheme, but uses a deeper total soil column and a deeper root system in the BATS. After the first year of simulation, the soil water content in RegZhang is progressively drained out of the soil column resulting in a deficit of rainfall in the Amazon. The RegClaris and RegArain, on the other hand, simulate a similar rainfall annual cycle in the Amazon, showing substantial improvement not only in phase but also in intensity. This improvement is partially related to an increase in evapotranspiration due to a larger availability of water in the soil column. A remote effect is also noted over the La Plata Basin region, where the larger summer rainfall rate may be related to the increase in moisture transport from the Amazon. Wind- and rainfall-based indices are applied to identify South American monsoon (SAM) timing. The RegClaris rainfall rates are adequate to identify the onset and the demise of SAM according to the observed data, whereas the rainfall deficit in RegZhang is associated with a delay in the onset and an early demise of the SAM.

Left ventricular thrombus attenuation characterization in cardiac computed tomography angiography

BACKGROUND: Because of their similar visual appearance, differentiation of left ventricular thrombotic material and myocardial wall can be difficult in contrast-enhanced coronary computed tomography (CT) angiography. OBJECTIVE: We identified typical thrombi attenuation of left ventricular thrombi with the use of CT measurement. METHODS: Over a time period of 6 years; we retrospectively identified 31 patients who showed a left ventricular thrombus in CT angiography datasets. Patients underwent routine contrast cardiac CT to investigate coronary artery disease. CT attenuation of each thrombus was assessed in the 4-chamber view. CT densities were also determined in the ascending aorta, left ventricle, and myocardial wall both in the mid-septal and mid-lateral segments. The mean CT attenuation of thrombi and the difference between attenuation in thrombi, left ventricular cavity, and myocardial wall were determined. The ratio of attenuation values in thrombus versus aorta and myocardium versus aorta were also determined. RESULTS: Mean (+/- SD) CT attenuation of all left ventricular thrombi in 31 patients was 43.2 +/- 15.3 HU (range, 25-80 HU). Mean CT densities of septal and lateral myocardial wall were 102.9 +/- 23.1 HU (range, 63-155 HU) and 99.3 +/- 28.7 HU (range, 72-191 HU), respectively, and were thus significantly higher than the CT attenuation of thrombi (P < 0.001). A threshold of 65 HU yielded a sensitivity, specificity, and positive and negative predictive values of 94%, 97%, 94%, and 97%, respectively, to differentiate thrombus from the myocardial wall. The mean ratio between CT attenuation of thrombus and CT attenuation within the ascending aorta was 0.11 +/- 0.05 (range, 0.04-0.23), which was significantly lower compared with the mean ratio between CT attenuation of the myocardial wall and the CT attenuation within the ascending aorta. CONCLUSION: CT attenuation within left ventricular thrombi was significantly lower than myocardial attenuation in CT angiography datasets. Assessment of CT attenuation may contribute to the differentiation of thrombi. (C) 2012 Society of Cardiovascular Computed Tomography. All rights reserved.

Effect of N-acetylcysteine on markers of skeletal muscle injury after fatiguing contractile activity

The effects of N-Acetylcysteine (NAC), an unspecific antioxidant, on fatiguing contractile activity-induced injury were investigated. Twenty-four male Wistar rats were randomly assigned to two groups. The placebo group (N=12) received one injection of phosphate buffer (PBS) 1 h prior to contractile activity induced by electrical stimulation. The NAC group (NAC; N=12) received electrical stimulation for the same time period and NAC (500 mg/kg, i.p.) dissolved in PBS 1 h prior to electrical stimulation. The contralateral hindlimb was used as a control, except in the analysis of plasma enzyme activities, when a control group (rats placebo group not electrically stimulated and not treated) was included. The following parameters were measured: tetanic force, muscle fatigue, plasma activities of creatine kinase (CK) and lactate dehydrogenase (LDH), changes in muscle vascular permeability using Evans blue dye (EBD), muscle content of reactive oxygen species (ROS) and thiobarbituric acid-reactive substances (TBARS) and myeloperoxidase (MPO) activity. Muscle fatigue was delayed and tetanic force was preserved in NAC-treated rats. NAC treatment decreased plasma CK and LDH activities. The content of muscle-derived ROS, TBARS, EBD and MPO activity in both gastrocnemius and soleus muscles were also decreased by NAC pre-treatment. Thus, NAC has a protective effect against injury induced by fatiguing contractile activity in skeletal muscle.

The polysurvival model with long-term survivors

Long-term survival models have historically been considered for analyzing time-to-event data with long-term survivors fraction. However, situations in which a fraction (1 - p) of systems is subject to failure from independent competing causes of failure, while the remaining proportion p is cured or has not presented the event of interest during the time period of the study, have not been fully considered in the literature. In order to accommodate such situations, we present in this paper a new long-term survival model. Maximum likelihood estimation procedure is discussed as well as interval estimation and hypothesis tests. A real dataset illustrates the methodology.

Influence of Modifications to the Pechini Method on the Electroactivity and Stability of Pt-RuOx/C Catalysts

Since electrode electroactivity and stability depend directly on the nature, morphology, and structure of the material, we have investigated how modifications to the Pechini method during the synthesis of Pt-RuOx/C electrocatalysts affected catalyst activity. The structure and stability of the resulting materials were investigated after their submission to a large number of potential scans and to constant potential for a prolonged time period in sulfuric acid 0.5 mol L-1 and methanol 0.1 mol L-1 solution. DMFC tests were accomplished using membrane electrode assemblies (MEAs) prepared by hot-pressing a pretreated Nafion 117 membrane together with the prepared Pt-RuOx anodes and a Pt cathode (from E-TEK), in order to compare the catalytic activity of the materials prepared by different methods. The stability studies demonstrated that the catalyst whose resin/carbon support mixture was agitated in a balls mill before undergoing heat-treatment was more stable than the other prepared catalysts. The catalysts synthesized with the single resin consisting of Pt and Ru and subjected to ultrasound before heat-treatment furnished the highest power density in the single fuel cell. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.011208jes]