Occurrence Of Difficulties Research Articles

Analisis Kesulitan Belajar Matematika Siswa Di Kelas VI SD Negeri 101944 Deli Muda


 
 
 
 Decreased student learning outcomes indicate the occurrence of difficulties in learning. This research was conducted to determine students' learning difficulties in mathematics in grade VI, the level of students' learning difficulties in mathematics, and to find out the causes of students' learning difficulties in mathematics in class VI SD Negeri 101944 Deli Muda. The research design is descriptive analysis, where this research uses quantitative research methods. the level of learning difficulties of students, especially in learning mathematics in class VI amounted to 63.1% which were identified as having learning difficulties in class, or in other words there were 12 out of 19 students / I who experienced learning difficulties with the type of learning difficulties in mathematics (Discalculia) which included difficulties in understand the concept of arithmetic in the material for addition of integers, mixed arithmetic operations, and understand how to solve problems in the material for solving area and perimeter problems in plane and geometric shapes. There is 5.2% at the level of difficulty with the type of reading difficulty or (dyslexia) or in other words there is 1 student who experiences an error when reading the questions. The level of difficulty with the type of writing learning difficulty (Disgraphia) is 0%, because there are no students in grade VI who have difficulty writing. There are several factors that cause learning difficulties in mathematics to occur, namely internal factors that occur from within the student, which include student interest and motivation in learning, study habits, and the health condition of the student's body. While external factors that occur from outside the student's self, which include environmental conditions, the relationship between teacher and student, and media/learning aids.
 
 
 

SOCIAL SUPPORT AND LONELINESS AS DETERMINANTS OF THE ONSET OF DISABILITY AMONG PUERTO RICAN OLDER ADULTS

Abstract Background The effect of loneliness and social support on health is poorly understood among older Puerto Ricans. As family size continues to decrease in Puerto Rico due to out-migration, a higher number of older adults have fewer family members to rely on, which may lead to detrimental health outcomes.Method: Using both waves (2002-03 and 2006-07) of the Puerto Rican Elderly: Health Conditions database, we examined the association between social support, living alone, and incident disability among a sample of older adults over 60 years of age residing in Puerto Rico. Disability was defined as the occurrence of difficulties with Activities of Daily Living (ADLs). Results 13.4% of older adults in our sample developed some form of disability. Older adults who developed a disability indicated receiving higher levels of social support (2.04 vs. 1.64) and loneliness (30.7% vs. 22.8%). Using multivariate logistic regression, we found that receiving social support increased the odds of developing a disability by 17% (OR: 1.17; CI: 1.02 – 1.35). Older adults who live alone had 58% higher odds of developing a disability (OR: 1.58; CI: 1.01 – 2.46). Conclusion The presence of social support and loneliness was correlated with a population prone to developing disabilities. Our findings concur with the well-established literature on psychosocial determinants in late life. However, this study represents the first attempt to understand psychosocial measures and disability in Puerto Rico. Public health organizations and healthcare systems must develop new societal mechanisms of support for older adults at risk of developing disabilities.

SOCIAL SUPPORT AND LONELINESS AS DETERMINANTS OF THE ONSET OF DISABILITY AMONG PUERTO RICAN OLDER ADULTS

Abstract Background The effect of loneliness and social support on health is poorly understood among older Puerto Ricans. As family size continues to decrease in Puerto Rico due to out-migration, a higher number of older adults have fewer family members to rely on, which may lead to detrimental health outcomes.Method: Using both waves (2002-03 and 2006-07) of the Puerto Rican Elderly: Health Conditions database, we examined the association between social support, living alone, and incident disability among a sample of older adults over 60 years of age residing in Puerto Rico. Disability was defined as the occurrence of difficulties with Activities of Daily Living (ADLs). Results 13.4% of older adults in our sample developed some form of disability. Older adults who developed a disability indicated receiving higher levels of social support (2.04 vs. 1.64) and loneliness (30.7% vs. 22.8%). Using multivariate logistic regression, we found that receiving social support increased the odds of developing a disability by 17% (OR: 1.17; CI: 1.02 – 1.35). Older adults who live alone had 58% higher odds of developing a disability (OR: 1.58; CI: 1.01 – 2.46). Conclusion The presence of social support and loneliness was correlated with a population prone to developing disabilities. Our findings concur with the well-established literature on psychosocial determinants in late life. However, this study represents the first attempt to understand psychosocial measures and disability in Puerto Rico. Public health organizations and healthcare systems must develop new societal mechanisms of support for older adults at risk of developing disabilities.

Prevalence of Sleep Hygiene Awareness, Practices and Quality among Elementary School Students in Canada

Enough sleep is crucial for physical and emotional growth of kids and students. It has been noted that there is a progressive decline in bedtime as kids turn into teens, despite the fact that the need for sleep among students does not decrease. Teenagers need for sleep has been estimated as much as 9.2 h per day. Poor sleep has actually been noted to lead to poor diet regimen, excessive weight, stunted growth, psychological health concerns, as well as chemical abuse. Much as the need for sleep is an individual particular, approximately at least 8.3 hrs. of rest per evening is recommended for teens, to avoid excessive daytime drowsiness. High quality sleep is necessary for young professional athletes for making sure much better performance in psychomotor as well as cognitive activities, and for minimizing the chances of creating challenging factors for musculoskeletal discomfort. Detection of sleep disorders in adolescent complaining of sleeplessness is a day-to-day challenge for doctors and clients alike. The purpose of the research study was to assess the prevalence of sleep hygiene awareness, practices and quality among elementary schools students in Canada. The study was a literature based. The research discovered that a boost in the occurrence of difficulty in getting sleep and in too much screen time exposure and marginal increase in physical activity levels. In addition, teens exceeding 2-h everyday display time had 20% higher probabilities of reporting sleep-onset problems, while no association was discovered for physical activity. The study also discovered that a regular every night routine aids the body recognize that it is going to bed; this could consist of taking warm shower or bathroom, checking out a publication, or light stretches. Whenever feasible it is essential for the students to try to avoid emotionally distressing conversations and activities before attempting to sleep considering that maintaining a routine sleep timetable also on weekends keeps the timing of the body's body clock and also can aid you fall asleep and wake up much more quickly. Based on the finding, the research study concluded that the daily substances that students take, the medicines one takes, how long they sleep in a day and exactly how they choose to invest their nights can considerably influence their quality of sleep. Also a couple of mild adjustments can, in many cases indicate the difference between sound rest as well as a restless evening. Finishing a two-week rest diary can help one understand how their routines impact their sleep. The study suggested that teenagers must reserve no more than eight hrs. For sleep given that the suggested quantity of sleep for a healthy grownup goes to least 7 hrs. Keywords: Sleep Hygiene, Awareness, Sleep Quality, Sleep Disorder, Students

The concept of the possibility of resettlement of compatriots in Russia

For a long time in Russia there is a problem of not so much a decrease in the total population, but a deterioration in its quality. In particular, this is due to the problem of brain drain (brain drain), which began massively in the 90s. At the beginning of the 21st century, attempts began to address this issue, including — since 2007, a program of return resettlement of compatriots was launched. Currently, it places a certain emphasis on the resettlement of precisely “talented compatriots”, however, there are no real results. The main problems of resettlement are: finding a job, housing, studying children and partly — difficulties in obtaining citizenship. In this paper, an attempt was made to find out the occurrence of difficulties in finding a workplace, since in fact “talented people are needed by everyone” and conclusions were drawn about the real complexity of integrating into the Russian reality of a talented person from abroad.

Delegitimization of leadership in overcoming difficulties in online learning during the COVID-19 pandemic

The general goal is not only to map the forms of difficulties in online learning, but also to analyze the reasons for the delegitimization of teacher. The specific purposes of this study are: (1) Delegitimization of teachers due to online learning, (2) The teacher's response to the pandemic condition, and (3) the implications of delegitimization on the teacher's life. This study used qualitative methods to explore primary and secondary data sources. The results of this study show (1) the occurrence of online learning difficulties as a form of delegitimization of teacher; (2) the occurrence of difficulties in establishing communication patterns, allocation of free time, innovation of activities that have a positive effect; and (3) there is a loss of identity, and teacher commitment in overcoming the difficulties of online learning. This paper concludes that there has been a delegitimization of teachers in online learning during the COVID-19 pandemic.
 
 Keywords: Deligimation, Leadership, Difficulties, Online Learning, COVID-19 Pandemic

Students in Hungarian Higher Education and Their Perception of Dificulties During Their Studies

Our research aims to examine the recruitment of students who experience difficulties with learning during their higher education studies and the motives behind their career choices, as well as the correlation of these factors with student persistence. The topicality of the problem stems from the diversity of students as a result of the expansion of higher education, as well as the increasing proportion of reading comprehension and other learning difficulties that can hinder individuals' progress in the labour market. Previous research has linked problems in learning in higher education to underdeveloped skills. However, we hypothesize that the occurrence of difficulties during students' studies and careers is determined by career choices, which are influenced by social background. While in higher education the social status differences of the family background already seem to disappear, the origin also affects the higher education career. To test the viability of this assumption, statistical methods were used to analyze the CHERD-Hungary database PERSIST -2019. In the case of difficulties and low persistence, we found a relationship with the career choice patterns of the students studied, especially with family factors influencing career choice and students' interest in their current education. One of our most important findings is that students who experience difficulties during learning can be divided into two groups. One group is characterized by low social status indicators, participating in low prestige and high risk fields of education, and there are specific cultural disadvantages in the background of their difficulties. The other group includes students who come from a higher-status family and concentrate on higher-risk but more prestigious courses, characterized by above-average selectivity and a higher risk of dropping out.

The decrease of histomorphometry and function of pancreas in male albino rats after induced by sleep deprivation

Background: Sleep disturbance accelerates type 2 diabetes mellitus by reducing insulin secretion and by the occurrence of difficulty in controlling sleep behaviour in humans so that it is necessary conduct a study by using experimental animals.Objective: This study aims to determine histophotometric differences of pancreas and differences of glucose tolerance in male albino rats (Rattus norvegicus) after induced by stress paradoxical sleep deprivation (PSD) and total sleep deprivation (TSD). Methods: This study applied a post-test only with control groups consisting of 30 male albino rats (Wistar strain) divided randomly into 3 groups: control group, PSD group and TSD group. The mean number and diameter of islets of Langerhans were calculated per slide and were averaged for each group at a magnification of 400 X. The percentage of beta cells in one islet of Langerhans was (ß-p) that was a number of normal beta cells (Bn) divided for the total beta cells (Bt) (normal and damaged) x 100%. The glucose level based on the sampling time was made a curve shape, and the area under the 0-to-120-minute curves (AUC0-120) was calculated by using a trapezoidal formula.Results: The lowest AUC0-120 level of glucose was the control group (14,082 ± 955mg/dL) and the highest was the TSD group (16,293 ± 2,195 mg/dL); the Post-Hoc LSD test showed a significant difference (p<0.05) between the control-PSD group and the TSD-control group. The mean result of pancreatic ß cells mass with the lowest number was in the TSD group (76.3 ± 4.8), and the highest result was in the control group (94.3 ± 2.7); Post-Hoc LSD showed a significant difference (p <0.05) in the control-PSD group and the TSD-control group. The lowest mean in cell diameter of islets of Langerhans was in the TSD group (0.132 ± 0.031 mm), and the highest mean was in the control group (0.213 ± 0.019 mm). Conclusion: Sleep deprivation could reduce pancreatic ß cell mass and cell diameter of islets of Langerhans and increase glucose tolerance levels.

Covid-19 Accelerates Digital Transformation in Industries: Challenges, Issues, Barriers and Problems in Transformation

Market emphasizes the need for a strategic view of the digital transformation of business, where transformation signifies a trend that allows changes in the core business processes and contributes to the development of sustainable business models. Complexity of the business transformation process affects the emergence of certain challenges and problems that need to be overcome on the way to creating innovative business models that will enable the use of full organizational potential. Purpose of this research is to delineate the various difficulties in digital transformation and determine what are the challenges, issues, barriers, and problems that organizations face in the desire to transform business. Paper presents a review of the literature of relevant research bases, where a qualitative and quantitative analysis of the results was made. Results show the frequency of occurrence of certain difficulties in DT within four categories - challenges, issues, barriers and problems, but also the occurrence of difficulties in the inevitable transformation due to the Covid-19 pandemic. It can be said that the pandemic has affected rapid adjustments, but also changes in the business models of organizations and that it has indirectly initiated digital transformation projects within organizations accompanied by various challenges, issues, barriers, and problems.

Surgical Results of Limb Lengthening at the Femur, Tibia, and Humerus in Patients with Achondroplasia.

BackgroundResults of limb lengthening in patients with achondroplasia were previously reported in many studies. However, the reports of comparison among the three long bones (femur, tibia, and humerus) are rare, especially for the results of crossed lengthening (lengthening of one femur and contralateral tibia followed by that of the opposite side) for the lower limbs. The purpose of this study was to report the surgical results of a series of limb lengthening in achondroplastic or hypochondroplasia patients at our institution.MethodsFifteen patients (14 with achondroplasia and 1 with hypochondroplasia) underwent lower limb lengthening of the femur (n = 32) and tibia (n = 28), and 12 of them underwent crossed lengthening. Humeral lengthening was performed in 14 patients (n = 28). The mean age at the first operation was 11.7 years, and the mean follow-up duration was 66.7 months. The healing index, consolidation period index (duration of consolidation period/gained length), and other radiographic indices were analyzed. Limb length discrepancy and hip-knee-ankle alignment in lower limbs, and the occurrence of difficulties were assessed.ResultsThe average gain in length for the femur, tibia, and humerus was 8.3 cm, 8.5 cm, and 7.4 cm, respectively. The mean healing index was 29.6 days/cm for the femur, 29.0 days/cm for the tibia, and 27.2 days/cm for the humerus. The mean consolidation period index was 14.7 days/cm for the humerus, which was significantly lower than that in the lower limb (17.3 days/cm for the femur and 17.8 days/cm for the tibia). Of the 12 who underwent crossed lengthening, five showed limb length discrepancy ≥ 1.0 cm. Among their 24 lower limbs, three showed valgus alignment ≥ 5° and one showed varus alignment ≥ 5°. Thirty-two pin site infections and three fractures were conservatively managed. Three femoral fractures, eight equinus deformities, and four cases with premature consolidation of the fibula were surgically treated. Obstacle and true complication related to humeral lengthening were not observed.ConclusionsHumeral lengthening was relatively effective and safe. Careful attention will be needed to avoid the occurrence of limb length discrepancy or malalignment in crossed lengthening.

The Impact of Disease-Modifying Therapy Access Barriers on People With Multiple Sclerosis: Mixed-Methods Study.

BackgroundIn the United States, people with relapsing-remitting multiple sclerosis (RRMS) can face difficulty accessing disease-modifying therapies (DMTs) because of insurance, pharmacy, or provider policies. These barriers have been associated with poor adherence and negative health outcomes.ObjectiveThe goals of this study were to describe the overall occurrence of difficulties and delays associated with gaining access to DMTs among people with RRMS, to assess DMT adherence during periods of reduced access, and to contextualize the patients’ journey from receipt of a prescription for DMT to obtaining and taking their medication when faced with access barriers.MethodsWe recruited US-based adults self-reporting RRMS from a Web-based health data-sharing social network, PatientsLikeMe. Individuals were invited to complete a Web-based survey if they reported a diagnosis of RRMS and were prescribed a DMT for MS. Follow-up phone interviews were conducted with 10 respondents who reported experiencing an MS-related relapse during the time they had experienced challenges accessing DMTs.ResultsAmong 507 survey completers, nearly half were either currently experiencing an issue related to DMT assess or had difficulty accessing a DMT in the past (233/507, 46.0%). The most frequently reported reasons for access difficulty were authorization requirements by insurance companies (past issues: 78/182, 42.9%; current issues: 9/42, 21%) and high out-of-pocket costs (past issues: 54/182, 29.7%; current issues: 13/42, 31%). About half (20/39, 51%) of participants with current access issues and over a third (68/165, 41.2%) of those with past issues went without their medication until they could access their prescribed DMT. Relapses were reported during periods of reduced DMT access for almost half (56/118, 47.5%) of those with past issues and nearly half (22/45, 49%) of those with current issues. Resolving access issues involved multiple stakeholder agents often coordinated in a patient-led effort. Among those who had resolved issues, about half (57/119, 47.9%) reported that doctors or office staff were involved, under half (48/119, 40.3%) were involved themselves, and about a third (39/119, 32.8%) reported the drug manufacturer was involved in resolving the issue. Follow-up interviews revealed that the financial burden associated with obtaining a prescribed DMT led to nonadherence. Additionally, participants felt that DMT treatment delays and stress associated with obtaining the DMT triggered relapses or worsened their MS.ConclusionsThis study expands current research by using a patient-centered, mixed-methods approach to describe barriers to MS treatment, the process to resolve barriers, and the perceived impact of treatment barriers on outcomes. Issues related to DMT access occur frequently, with individuals often serving as their own agents when navigating access difficulties to obtain their medication(s). Support for resolution of DMT access is needed to prevent undue stress and nonadherence.

Dekomposisi Genetik tentang Hambatan Mahasiswa dalam Menerapkan Sifat-sifat Turunan

Limit was to basic concept of derivative. The results of previous research found that learners have obstacles in understanding the limit function, consequently, the occurrence of difficulties and mistakes learners understand the concept and derived principles. This study aims to determine the obstacles of learners in applying derived properties. The approach of this research is qualitative by applying task-based interview with subject of 10 students selected by certain condition from 70 students in Mathematics Education Study Program of University of Bengkulu. The researcher is the main instrument in this research which is guided by the interview sheet and duty sheet. Data analysis was performed by genetic decomposition analysis. The results of this study indicate that the barriers of learners in applying analytic concepts and properties analytically include, the tangent line almost parallel to the y-axis, the break point (cusp) at x = -4, the second derivative, the extreme point, the emergence of contradictions, asymptotes flat, and do not understand conceptually. To overcome the obstacles of learners in understanding the concept and the nature of derivatives and its application, it is suggested to apply the mathematics learning model based on the extended triad++.

Parental rearing styles as the predictors of internalised and externalised problems of adolescents

Adolescence is a period that bears a particular risk for the occurrence of difficulties in psychosocial adaptation. This research was aimed at investigating the predictive power of father?s and mother?s rearing styles for the level of internalised (more specifically, anxiety as a trait) and externalised problems on the sample of adolescents (212), aged 12 to 18. The following instruments were used in data collection: the Parental Rearing Style Scale, the Strengths and Difficulties Questionnaire (SDQ) and the State-Trait Anxiety Inventory (STAI-Y). The obtained results indicate that an emotionally cold father?s style of rearing and the restricting style of rearing of both parents are significant predictors of the level of general anxiety. When it comes to externalisation, it is shown that cold father?s style of rearing is the only significant predictor. The results may contribute to a better understanding of the adaptive capacities of a child and the family in coping with the critical phases in the development of children and youth.

Informal support for the elderly in the context of their living arrangements in selected European countries

The main objective of this paper is to analyze the informal support for the elderly experiencing problems in everyday life connected with physical, mental or emotional fitness. The analysis covers groups of countries chosen from the participants of SHARE project. The multinomial logit model has been used in order to verify the hypothesis that such problems determine the living arrangements of the elderly. The binomial regression model has been used in order to answer a question if informal support from outside the household obtained by the people experiencing problems in everyday life is determined by the type of the household and by social and demographic characteristics of the individuals receiving the support. In conclusion we state that the occurrence of difficulties in everyday life does not affect the chance of living in a one-person household. For the other types of the households the aforementioned influence turns out to be significant only for selected countries. In all investigated countries, for people experiencing difficulties in everyday life, a significant influence of the type of the household on receiving help from outside the household has been observed. In future research, a closer attention should be paid to elderly people living alone and to incorporating various types of limitations in everyday life separately for men and women. For better explanation of the differences between post-transitional and the other European countries the formal and institutional supports should be introduced.

Assessment of Factors Associated With Surgical Difficulty During Removal of Impacted Maxillary Third Molars

Estimating the difficulty of removing third molars is a common dilemma. However, the estimation of the difficulty associated with maxillary third molar surgery has not yet been defined. The aim of the present study was to determine the degree of difficulty and identify predictor variables associated with the occurrence of difficulty in the removal of impacted maxillary third molars. A prospective cohort study was carried out involving patients who underwent at least 1 surgical removal of an impacted maxillary third molar at the Oral and Maxillofacial Surgery Unit, University of Pernambuco (Pernambuco, Brazil). Predictor variables indicative of surgical difficulty were classified by their demographic, clinical, and radiographic aspects. Degree of surgical difficulty was categorized as low, moderate, or high based on the surgical technique used. Descriptive and bivariate statistics were computed. In total, 106 patients fulfilled the eligibility criteria and 204 surgeries were performed. Patients' mean age was 22.8 ± 2.2 years and the proportion of women to men was 3:1. Approximately 20% of patients were overweight. Surgical difficulty was generally low and 5 variables were significantly associated with the occurrence of a high degree of surgical difficulty. Surgical difficulty during the removal of impacted maxillary third molars is generally low. However, for cases with a high degree of difficulty, identification of predictor variables may be useful for students and inexperienced clinicians to consider the decision not to execute the procedure, thus avoiding complications that often require complex management.

Efficacy of Hydroxypropyl Cellulose Ophthalmic Inserts (LACRISERT) in Subsets of Patients With Dry Eye Syndrome: Findings From a Patient Registry

To determine acceptability and efficacy of hydroxypropyl cellulose ophthalmic inserts in patients with dry eye syndrome (DES) and additional comorbidities. A multicenter, 2-visit, open-label, 4-week registry study. Five hundred twenty patients were recruited to the intent-to-treat group. Four hundred eighteen patients completed the study including 86 contact lens wearers, 79 with cataract diagnosis, 52 with prior cataract surgery, 22 with prior laser-assisted in situ keratomileusis, and 15 with glaucoma. Patient questionnaires were completed at baseline and after 4 weeks of treatment to assess mean change in severity of DES symptoms, ocular surface disease index (OSDI) scores, frequency of occurrence of DES symptoms, occurrence of difficulty when performing activities of daily living (ADLs), and frequency of discomfort in various environmental conditions. Mean change was measured from visit 1 to visit 2. Symptoms, OSDI scores, and measure of degree of difficulty when performing ADLs. Four hundred eighteen patients completed the study. Compared with baseline, this population of patients demonstrated statistically significant improvements in mean OSDI scores (P = 0.0215) and symptoms of discomfort, burning, dryness, grittiness, stinging, and light sensitivity (P < 0.05). Mean improvement in OSDI scores of patients in the 5 identified subsets of patients with comorbid conditions were significant for patients using contact lenses (P < 0.025), who had undergone prior cataract surgery (P < 0.04), and with prior laser-assisted in situ keratomileusis surgery (P < 0.05). Patients diagnosed with cataracts or glaucoma did not show significant changes in any measures in this study. Patients with DES and comorbid conditions experienced relief of symptoms and benefit to ADLs and quality of life similar to patients without comorbid conditions. In subsets of patients with moderate to severe DES and comorbid conditions, hydroxypropyl cellulose ophthalmic inserts improve the symptoms of DES, ability to perform ADLs, and quality of life. The reported benefits may be additive to those seen with patients' existing therapies.

The act of interpretation

The author understands the interpreting act as an attempt to perceive what happens in the transference/countertransference fi eld and not just what happens in the patient's mind. Interpretation transcends mere intellectual communication. It is also an experience in which analysts’ emotions work as an important instrument in understanding their patients. Interpretation is seen to possess manifest as well as latent content; the latter would contain the analysts’ feelings, emotions and personality. The unconscious content of an interpretation does not inconvenience or preclude the development of the analytic process, but, on the contrary, it allows new associative material to emerge, and it transforms the analytic session into a human relationship. Analysts’ awareness of this content derived from patients’ apperceptions is a signifi cant instrument for understanding what is happening in the analytic relationship, and what transpires in these sessions provides fundamental elements for analysts’ self‐analysis. Some clinical examples demonstrate these occurrences in analytic sessions, and how they can be apprehended and used for a better understanding of the patient. The author also mentions the occurrence of diffi culties during the analytic process. These diffi culties are often the result of lapses in an analyst's perception related to unconscious elements of the relationship.

ELECTROPHYSIOLOGICAL FINDINGS IN RATS WITH EXPERIMENTAL CARBON DISULPHIDE NEUROPATHY

Electrophysiological findings in rats with experimental carbon disulphide neuropathyRats were subjected to the inhalation of 750 parts/106 of carbon disulphide for 6 h daily, 12 rats being exposed for 22 weeks, and 15 rats from 2 to 5 weeks. The development of neuropathy was monitored bimonthly by measurement of the motor conduction velocity (MCV) in the sciatic nerve. A slight, but statistically significant slowing of the MCV was observable at 2 weeks, although no further reduction occurred during the following 3 weeks. Marked slowing of the MCV was demonstrated, concomitantly with the occurrence of difficulties in voluntary control of the hind limbs, at 8 weeks of exposure. After 22 weeks of exposure, 4 rats were allowed to recover for a further 12 weeks. Slight improvement in their MCV was observed, but it remained at a much lower level than that in the control group. No permanent alteration in the MCV occurred in those animals exposed for up to 5 weeks.