The Premedical Student: His Progress: A Study of a Cohort of Premedical Students at the University of British Columbia

Since September 1961, a prospective study of premedical and science students has been conducted at the University of British Columbia. On completion of their sophomore year, after a year of changes from one group to another or withdrawal from either group, only 82 students existed in the diminished Premedical cohort while 137 students existed in the augmented Science cohort. These two groups have now become similar demographically, and their academic potential, as indicated by achievement and ability tests, has also become similar in terms of their mean test scores. In academic performance the present Premedical cohort has displayed some superiority over the Science cohort in high school, freshman and sophomore years. The sophomore premedical mean grade was 66.0% compared with 63.7% for the Science cohort. The hypothesis is developed that these findings reflect a difference in motivation, and therefore that perception of ultimate career goals will motivate and affect academic performance of students in their undergraduate years.     

The Premedical Education of the First-Year Class in Canadian Medical Schools: 1965-66

The premedical academic records of the 1965-66 entering class of Canadian medical students were analysed. Ninety-six per cent of the class had taken their preparation in a Canadian institution, while 80% had taken it in the same university as the medical school in which they enrolled. Forty per cent entered without a degree, the remainder having at least a bachelor''s degree in arts or science.Thirty-six per cent of all courses taken by these students in their premedical education were in the physical sciences, 22% in the biological sciences and 41% in the social sciences and humanities. One-third of the students had taken no course in the behavioural sciences and another third had taken only one course.Analysis of the level of performance of the entering class showed that 10% had obtained an A average, 49% a B average, 41% a C average and 3% a D average. The grades of these students were higher generally in the natural sciences than in the social sciences or humanities.It was concluded that it could be questioned whether medical students received a premedical preparation which met the philosophy of a “broad, liberal education”.     

Medicine or Science—A Study of Career Decisions

A study of the career decisions of all students in a single matriculation cohort was undertaken in 1965 at the University of British Columbia. Studied were 64 premedical students, 112 ex-premedical students and 87 science students who had completed at least their second year. It was found by means of a questionnaire that medicine remained the career of high prestige for the three groups of students. In general the values and needs of the ex-premedical student were more similar to those of the science student than the premedical student. The loyalists to medicine were found to be more committed, self-assured, and orientated towards people and service. In addition, the premedical student was more concerned about his academic achievement but was also more confident of his progress. He emerged at the end of his training as the committed student who had chosen medicine at an early age and had remained loyal to his chosen career goal.     

Competencies in premedical and medical education: the AAMC-HHMI report

One hundred years ago, Flexner emphasized the importance of science in medicine and medical education. Over the subsequent years, science education in the premedical and medical curricula has changed little, in spite of the vast changes in the biomedical sciences. The National Research Council, in their report Bio 2010, noted that the premedical curriculum caused many students to lose interest in medicine and in the biological sciences in general. Many medical students and physicians have come to view the premedical curriculum as of limited relevance to medicine and designed more as a screening mechanism for medical school admission. To address this, the Association of American Medical Colleges and the Howard Hughes Medical Institute formed a committee to evaluate the premedical and medical school science curricula. The committee made a number of recommendations that are summarized in this essay. Most important were that competencies replace course requirements and that the physical sciences and mathematics be better integrated with the biological sciences and medicine. The goal is that all physicians possess a strong scientific knowledge base and come to appreciate the importance of this to the practice of medicine. While science education needs to evolve, Flexner's vision is as relevant today as it was 100 years ago.     

Veterinary Students’ Beliefs About Animal Sentience: What Role Does Gender Play?

ABSTRACT

Across a 15-year period, annual cohorts of first-year veterinary science students (n = 1,380; 77% female) at a British university completed the Belief in Animal Sentience (BiAS) questionnaire, in which they reported their beliefs about the sentience (capacity to feel) of ten species: dogs, cats, lions, pigs, sheep, rats, rabbits, chickens, bees, and spiders. On the basis of previous findings regarding people’s beliefs about animals’ capacities for mind, it was hypothesized that female students would ascribe more human-like sentience to animals than would male students. It was also hypothesized that the proportion of female students in each of the cohorts studied would have an influence on the beliefs of the year group as a whole: cohorts comprising a larger percentage of women would have higher animal sentience beliefs in both males and females. The data were analyzed using two-level regression models to concurrently investigate the effects of individual respondents’ gender and the percentage of female students in their cohort. Compared with their male counterparts, female veterinary students across all the cohorts studied attributed significantly higher (more human-like) sentience to each of the ten animals listed in the BiAS questionnaire, but the percentage of female students in each year group was not associated with students’ sentience beliefs. It was also found that childhood experience of having owned pet cats or dogs was related to students’ beliefs about the sentience of these species, although this association did not contribute to the differences found between male and female respondents. Given the increasing number of women entering the veterinary profession, and previous findings that beliefs about animals’ capacities for sentience may be associated with the veterinary care they are given, we conclude that gender differences in sentience beliefs could have a significant impact on the future of veterinary practice and patient welfare.     

Influences of microclimatic conditions and water relations on seasonal leaf dimorphism of Prosopis glandulosa var. torreyana in the Sonoran Desert,California

Summary Seasonal measurements of microclimatic conditions were compared to seasonal indices of leaf structural components and plant water relations in Prosopis glandulosa var. torryana. P. glandulosa had two short periods of leaf production which resulted in two distinct even aged cohorts of leaves. The two leaf cohorts (summer, winter) were concurrent in the summer and fall, contrasting to previous studies on other species in which one leaf form replaces a previous leaf type. The structural characteristics of these two cohorts differed significantly in two replicate year cycles. The leaves of the spring cohort were larger in weight and area but similar to the summer cohort in specific leaf weight and leaflet number. The second growth period leaves constituted only a small proportion of the total plant leaf area. The dimorphism between the two cohorts was best associated with plant water relations and not energy load. Second growth period leaves maintained turgor to greater water deficits but lost turgor at higher leaf water potentials. Seasonal osmotic adjustment occurred for first growth period leaves but not second growth period leaves. The small leaves produced during the hot climate were most likely the result of low turgor potential during development rather than an adaptation to tolerate stressful environments.     

Life-history variation in the short-lived herb <Emphasis Type="Italic">Rorippa palustris</Emphasis>: effect of germination date and injury timing

Life-history variation in annuals is known to be caused by size requirements for photoinduction of flowering, but the importance of germination date and injury was overlooked so far even though they may play an important role in disturbed habitats. To test the effect of germination date and timing of injury on life-history variation of an annual plant, we performed a 2-year pot experiment with the root-sprouting herb Rorippa palustris. Plants belonging to six different cohorts, and sown at monthly intervals from April to September, were injured (all stem parts removed) in three ontogenetic stages: vegetative rosettes, flowering plants and fruiting plants. Plants from the April, and partly from the May, cohort behaved as summer annuals: they started to bolt at the same time, resprouted and overwintered poorly. Plants from the June cohort flowered in the first season as well, but they entered the bolting stage a month later than the preceding cohorts, produced the least fruits, but overwintered successfully and flowered again the second year (polycarpic perennials). Cohorts germinating after the summer solstice did not flower during the first year and, with the exception of the September cohort, overwintered successfully and flowered the second year (winter annuals). After injury, the pattern of life-histories was the same as in control plants, although generative reproduction was interrupted by injury in the first year of the experiment. About one quarter of␣plants injured in the vegetative stage regenerated after injury irrespective of cohort, however, regeneration was enhanced in larger plants. Regeneration of plants in the flowering and fruiting stages depended on date of injury in relation to day length, being the most successful after the summer solstice. Life-history variation, together with the ability to resprout after severe injury in the pioneer wetland herb Rorippa palustris is caused by its ability to germinate throughout the season. Even the second tested factor, the effect of injury, is modified by germination time. The experiment points to a complex nature of factors affecting life-history variation as well as resprouting after severe injury in short lived plants. An erratum to this article can be found at     

Life history of the ghost shrimp, Callianassa japonica Ortmann (Decapoda: Thalassinidea), on an intertidal sandflat in western Kyushu, Japan

Growth, density, survival, and reproduction were examined for the population of the ghost shrimp, Callianassa japonica Ortmann, inhabiting an intertidal sandflat in western Kyushu, Japan, based on samples collected from May, 1989 to April, 1991. During the breeding season (June–October) each year, there were two discrete periods of egg production by females. The post-larval settlement, with a time-lag of 1–1.5 months (brooding plus larval developmental periods), generated two major recruitment cohorts, occurring in July–August (1st cohort) and September–November (2nd cohort). The higher growth rate of individuals after recruitment in the 1st cohort enhanced the separation of the two cohorts. Between sexes, the subsequent life history patterns and population characteristics were, for the most part, similar. In females, the majority of individuals of each of the two cohorts matured after approximately one year, respectively, at around a 20-mm total body length, and a portion of these cohorts survived as a fused cohort until June of the second year, breeding again prior to dying off by the end of September. The pattern of growth was an indeterminate type. For each of the two cohorts, the growth rates changed at two transition points of their life history, at around the beginning of their two breeding seasons. The growth rate for the 1st cohort slowed down at the first transition point, while that for the 2nd cohort speeded up there. This led to the approach and fusion of the two cohorts near the second transition point, when growth stopped. During periods other than the breeding seasons, high survival rates were exhibited by the two cohorts. During the first breeding season, a significantly low survival rate was observed for the 1st cohort, but not for the 2nd cohort. The degree of participation in breeding activity may be responsible for the above differences between cohorts. In the two male cohorts, while the cost of reproduction did not reduce the growth rates during the first breeding season, it lowered their survival rates more severely compared to those of females. This may be responsible for the slightly female-biased sex ratio in the population (1.06:1). The density of the population as a whole was stable throughout the study period, with the mean ± SD being 901 ± 157/m² (n = 27); the adult population declines during the breeding seasons were effectively replenished by recruitment each year.     

Canadian fertility trends in perspective

This paper examines the broad movements of Canadian period and cohort fertility over the past 100 years, and compares them with corresponding trends in the US and other industrialized countries. The main movement in Canada was a decline in fertility extending from the 19th century to the present, interrupted in the 1940s and 1950s by a baby boom. Between 1871 and 1937 the total fertility rate (TFR) fell at about an average of 1.4% annually. The rate of fall in the US was similar, with the result that in the late 1930s the Canadian TFR was about 20% that of the US. The fertility boom that followed was steeper in the US than in Canada, and in the downswing that later followed, the rate of decline was similar in the 2 countries (3.4-4% annual average). But, the decline continued longer-- indeed still continues--in Canada, whereas the TFR in the US reached its lowest point in 1976. Moreover, the recent decline in fertility has been more severe in Canada than in almost any other industrialized country. The TFR relates to fertility in a single year and is highly sensitive to short-term changes in the timing of births. For the purposes of understanding and explaining long-term trends in fertility, the completed fertility rate (CFR) is a better index because it measures the ultimate family size of cohorts. Cohort fertility can be seen to fluctuate much less than does period fertility. In both the US and Canada, the peak cohorts, born in the early 1930s, had roughly the same completed fertility, and later cohorts continued to remain closely in step as the CFR fell sharply. In Canada the fall continues, though at a reduced rate, in the latest cohorts for which there is information. Apart from differences in amplitude, the dates of turning points and the shapes of the TFR and CFR curves of Canadian fertility are fairly similar. The long decline in cohort fertility is largely explained by the decrease in the proportions of families of 6 or more children. During the baby boom, for Catholics and non-Catholics alike, the proportion of ever-married women remaining childless fell by about 40%, the proportion having 2 children changed little, and the proportions having 3,4 and 5 children tended to increase substantially. The crucial difference between the 2 groups was in the proportions of women having 6 or more children. For non-Catholics, the proportion fell by over 4% from a high level. For non-Catholics, on the other hand, the proportion rose somewhat, though even after the rise, it was barely more than 1/2 the level to which the Catholic proportion had declined. Among Catholics, the effect of the massive decline in the proportion of women having 6 or more children was to swamp the effects of the increase in the proportions of women having 3, 4 and 5 children. The net effect was that fertility declined. Among non-Catholics, however, the comparable increases in the proportions of families of 3, 4 and 5 children, were not offset by any fall in the proportion of larger families, with the result that a baby boom occurred.     

Regression of moral reasoning during medical education: combined design study to evaluate the effect of clinical study years

Background

Moral reasoning is important for developing medical professionalism but current evidence for the relationship between education and moral reasoning does not clearly apply to medical students. We used a combined study design to test the effect of clinical teaching on moral reasoning.

Methods

We used the Defining Issues Test-2 as a measure of moral judgment, with 3 general moral schemas: Personal Interest, Maintaining Norms, and Postconventional Schema. The test was applied to 3 consecutive cohorts of second year students in 2002 (n = 207), 2003 (n = 192), and 2004 (n = 139), and to 707 students of all 6 study years in 2004 cross-sectional study. We also tested 298 age-matched controls without university education.

Results

In the cross-sectional study, there was significant main effect of the study year for Postconventional (F(5,679) = 3.67, P = 0.003) and Personal Interest scores (F(5,679) = 3.38, P = 0.005). There was no effect of the study year for Maintaining Norms scores. 3^rd year medical students scored higher on Postconventional schema score than all other study years (p<0.001). There were no statistically significant differences among 3 cohorts of 2^nd year medical students, demonstrating the absence of cohort or point-of-measurement effects. Longitudinal study of 3 cohorts demonstrated that students regressed from Postconventional to Maintaining Norms schema-based reasoning after entering the clinical part of the curriculum.

Interpretation

Our study demonstrated direct causative relationship between the regression in moral reasoning development and clinical teaching during medical curriculum. The reasons may include hierarchical organization of clinical practice, specific nature of moral dilemmas faced by medical students, and hidden medical curriculum.     

The relationship between pet ownership,social support,and internalizing symptoms in students from the first to fourth year of college

Abstract

Internalizing symptoms are prevalent in students as they enter and complete college. Considering research suggesting mental health benefits of pet ownership, this study explores the relationship between pet ownership, social support (SS), and internalizing symptoms (IS) in a cohort of students across their 4-year college experience. With no differences at college entry, students growing up with pets had greater IS through the fourth year, and greater SS through the third year, than those without pets. Currently living with a pet, gender, SS and personality predicted IS in the fourth year. Females experiencing higher IS in their first year are more likely to live with pets in their fourth year, and fourth year females living with pets or greatly missing absent pets have higher IS than females without pets or missing pets less. Findings suggest a unique relationship between IS in female students and their pet relationships not seen in males.     

Dynamics of cohorts of cladodes and related effects on reproduction in the shrub Retama sphaerocarpa in semi-arid south-eastern Spain

Changes in the size and age structure of the canopy of the leguminous shrub Retama sphaerocarpa in semi-arid south-eastern Spain were investigated by monitoring growth and survivorship of cladodes (photosynthetic stems) on marked shoots over a period of 26 months. Three basic morphological types of cladodes – long shoots, short shoots, and secondary short shoots – were distinguished.The canopy of the shrubs contained three annual cohorts of cladodes in spring and summer. The number and size of shoots produced each year was highly variable and was apparently related to the amount of rainfall during the preceding cool season. The spring cohort of 1994 produced only 37% of cladodes compared with 1993. Two cohorts of shoots were actually initiated in spring and late summer of each year, but the second cohort produced only 2–12% of the number of cladodes compared with the spring cohort. The proportions of the different cohorts in the canopy changed rapidly from April to August, but only slowly during the remainder of the year when only two annual cohorts remained after extensive litterfall in late summer. This late summer litterfall caused a substantial reduction in green canopy area (40–50%) which was achieved mainly be shedding of one year old cladodes. The life expectancy of cladodes decreased with increasing order of their morphological type from 850 ± 25 days in long shoots to 563 ± 4 days and 546 ± 9 days in short shoots and second order short shoots, respectively.Flowering and fruiting took place from May to July, almost exclusively on one year old cladodes, and coincided with the maximum development of the canopy. Flowering intensity was high in 1994, when individual shoots supported a mean number of approximately 150 flowers. Shoots produced an average of 12.6 ± 0.6 and 5.3 ± 1.0 fruits per shoot in 1993 and 1994, respectively. Most of the annual fruit crop (80–90%) was shed during litterfall in late summer. A proportion of 10–20% was retained in the canopy for up to 12 months, however, with some fruits persisting for more than 22 months.     

Rank relations of juvenile and subadult natal males of Barbary macaques (Macaca sylvanus) at Affenberg Salem

Rank relations of more than 100 juvenile and subadult natal Barbary macaque males were analyzed. Hierarchical relations among individuals of the same age were established early during the first year of life. With few exceptions concerning infants from very high-ranking genealogies, males dominated female peers regardless of maternal rank. Males started to outrank females from older cohorts during the second year of life and completed the process of rank reversal with adult females at 5-6 years of age. An age-graded dominance pattern existed among males from different birth cohorts. Only 3 rank reversals between males from different cohorts were observed. Rank reversals among males of the same birth cohort occurred more frequently. Rank position of a male among his male peers was influenced by birth order, by maternal rank, and by the presence of juvenile brothers. Most males without juvenile brothers had low positions, regardless of maternal rank. Males born late in the birth season were also low-ranking, even when juvenile brothers were present. There was no cohort where ranking among males was determined by maternal rank alone, as is the case in rhesus monkeys and Japanese macaques. Adult/subadult male carriers had no noticeable effect on rank positions of 'their' infants. It is suggested that a weaker influence of Barbary macaque mothers on rank of their sons is related to very early integration of male infants in male social/play groups.     

Variable photosynthetic acclimation in consecutive cohorts of Scots pine needles during 3 years of growth at elevated CO2 and elevated temperature

In this experiment, the photosynthetic acclimation of successive needle cohorts of Scots pine were studied during 3 years of growth at elevated CO₂ and temperature. Naturally regenerated Scots pine (Pinus sylvestris L.) trees were subjected to elevated CO₂ concentration (+CO₂, 700 p.p.m), elevated temperature (+T, ambient +2 to +6 °C) and to a combination of elevated CO₂ and temperature (+CO₂ + T) in closed‐top chambers, starting in August 1996. Trees growing in chambers with ambient CO₂ and ambient temperature served as controls (AmbC). Elevated CO₂ influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO₂ was higher at +CO₂ than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO₂ + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased. The interaction of +CO₂ and +T on Rubisco was mostly negative; consequently, in the second and third year of the experiment the carboxylation capacity decreased at +CO₂ + T. In the 1996, 1997 and 1998 cohorts, the structural N concentration of needles was lower at +CO₂ than at AmbC. Elevated CO₂ and elevated temperature generally had a positive interaction on N concentration; consequently, N concentration in needles decreased less at +CO₂ + T than at +CO₂. At +CO₂ + T, the acclimation response of needles varied between years and was more pronounced in the 1‐year‐old needles of the 1997 cohort than in those of the 1998 cohort. Thus, acclimation was not always greater in 1‐year‐old needles than in current‐year needles. In the +CO₂ + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO₂.     

Two size classes of 0+ year perch: is phenotypic plasticity based on food resources?

Perch Perca fluviatilis of age 0+ years were caught in a gravel pit lake in June (unimodal size distribution) and in July (bimodal size distribution) to analyse morphological differences between the two growth cohorts. Independent of size, 0+ year perch developed a deeper body and perch of the large size cohort had an even deeper body than perch of the small size cohort. This might have been adaptations to either piscivory or planktivory, but might also be a hint that 0+ year perch of the small size cohort were undernourished and that they developed on a different trajectory than individuals of the large size cohort. In a second step the study was extended with a mesocosm experiment. This part of the study was designed to provide preliminary evidence for the extent to which morphological variations may be due to the consumption of different food resources when other factors such as habitat use could be neglected. Two groups of 0+ year perch in four mesocosms were fed for 40 days with the same biomass of either plankton or cyprinids. Although the experimental groups at the end of the experiment did not differ in size, they differed in morphology. The mouth of the piscivorous 0+ year perch became larger, the pectoral fins and the centre of mass of the posterior abdomen were shifted backwards. These results provide further evidence that the type of food is important and might lead to further functional adaptations in morphology.     

Prevalence and risk factors of Human Papillomavirus (HPV) infection in southern Chinese women - a population-based study

Background

Persistent high-risk type Human papillomavirus (HPV) infection is recognized as a necessary cause of cervical cancer. This study aimed to compare the HPV prevalence and risk factors between women residing in Hong Kong (HK) and Guangzhou (GZ) region of China.

Methodology/Principal Findings

A total of 1,570 and 1,369 women were recruited from HK and GZ, respectively. The cytology samples were collected and tested for HPV infection. The overall and type-specific HPV prevalence and the potential risk factors for acquisition of HPV infection were studied. Women with normal cytology in the GZ cohort had significantly higher HPV prevalence (10%) than those in the HK cohort (6.2%, p<0.001). The patterns of the age-specific HPV prevalence were also different between the two cohorts. In the HK cohort, women at the age of 20–29 years old had the highest prevalence and a second peak was observed in the age of ≥60 years old. In the GZ cohort, the highest HPV prevalence was also observed in 20–29 years old but declined as the age increased and a second peak was not seen. HPV16 and HPV52 were the most common high-risk types found in the HK and GZ cohorts, respectively. Age was the most consistently observed independent risk factor for HPV infection in the HK, while the number of sexual partners had association in the GZ cohort.

Conclusions/Significance

Our study provides the current status and the epidemiological characteristics of HPV prevalence in Southern Chinese women. The results strongly suggested that population education and the effective cervical cancer screening would be vital in the prevention of cervical cancer.     

Persistence of Dactylogyrus eucalius (Monogenea: Dactylogyridae) on the short-lived host Culaea inconstans (Pisces: Gasterosteiformes)

The monogene Dactylogyrus eucalius Mizelle and Regensberger, 1945 and its ability to maintain a population from year to year on the annual fish Culaea inconstans Kirkland was examined in a small lake in central Ontario. Fish were sampled toward the end of their annual breeding season, at a time when the host population consisted of 2 cohorts, i.e., young-of-the-year (0+) and mature adults (1+). Prevalence of infection was 94%, with a mean intensity of 8.8 +/- 9.6; neither measure varied significantly with host length or between cohorts (P > 0.05). At necropsy, parasites were characterized as juveniles that included postoncomiracidia (immature, with a ventrally directed haptor) as well as developing protandrous males (body with a near-complete haptor and with little or no pigmented vitellaria), or as adults (with testis, ovarium, darkened vitellaria, and occasionally bearing a tanned egg). The proportion of juvenile to adult parasites differed significantly between cohorts (P < 0.05), with 0+ fish infected with a mixture of juveniles and adults, whereas 1+ fish had almost exclusively adult parasites. Since adult (1+) brook stickleback typically die after spawning, the increased frequency of juvenile parasites exploiting juvenile hosts may represent an evolutionary adaptation, maximizing the chances of parasites infecting hosts that will enter winter. It is suspected that 0+ fish can be infected in the nest within 2 wk of hatching and persist by effectively infecting new host recruits when they are sympatric with their parents.     

Changes in size and age at maturity in a population of kokanee Oncorhynchus nerka during a period of declining growth conditions

Trends in size distributions and age at maturity of spawning kokanee Oncorhynchus nerka during a 5 year period of declining growth conditions at Bucks Lake, California, U.S.A. were consistent with the hypothesis that reductions in growth rates in successive cohorts induce a shift to an older age at maturity. This forestalls decreases in size at maturity during a transitional period characterized by an increasing proportion of individuals that delay maturation. During the course of the study, kokanee first began declining in size at maturity, and then shifted from a 3 year to a 4 year egg to adult cycle. Individuals that spawned during their fourth year (age 3 years) were significantly larger, on average, than members of their cohort that spawned during their third year (age 2 years). This difference was greatest when age 2 year adults were smallest. The shift to an older age at maturity prevented a steady decline in size at maturity, even though age‐specific size was steadily declining over time. Size at maturity, however, began to decline again once the transition to a 4 year cycle was complete. In addition, there was a general trend of decreasing length‐specific mass. The data indicate that there is a range of growth trajectories over which delayed maturity can prevent a temporal pattern of decreasing size at maturity as growth rates decline.