Why do plankton matter? 91��ɫ biology Professor Norman Yan, the study’s senior author, says these tiny creatures are critical to our survival. “Without plankton, humans would be quite hungry and perhaps even dead. Much of the world's photosynthesis, the basis of all of our food, comes from the ocean's plankton. The oxygen in every other breath we take is a product of phytoplankton photosynthesis,” says Yan.

Norman Yan

Yan together with the study's lead author Howard Riessen, a professor of biology at SUNY College at Buffalo studied the effect of changes in water chemistry on plankton prey defenses. Specifically, they examined how lower calcium concentrations affect Daphnia (water flea) exoskeleton development. These low calcium levels are caused by loss of calcium from forest soils, a consequence of decades of acid rain and multiple cycles of logging and forest growth. The results are published this week in the Proceedings of the National Academy of Sciences.

Daphnia pulex

“At low calcium levels the organisms grow slower and cannot build their armour,” says Riessen. “Without suitable armour, they are vulnerable to ambush by predators,” he says.

“Calcium is a critical element for Daphnia and many other crustaceans,” Riessen says. “Daphnia build their exoskeletons, which include some defensive spines, with calcium to protect themselves from predators. Where calcium levels are low, the Daphnia have softer, smaller, exoskeletons with fewer defensive spines, making them an easy snack.”

This phenomenon of reduced calcium is also playing out on a much larger scale in the world’s oceans, notes Yan. “Increases in ocean acidity are complicating calcium acquisition by marine life, which is an under-reported effect of global carbon dioxide emissions. Thus marine plankton may also find themselves more vulnerable to predators,” he says.

Howard Riessen

The public is used to stories about changes in water chemistry that lead to large-scale fish kills, says Riessen. “These changes are more insidious. Daphnia might not be a household name, but they are food for fish, and they help keep our lakes clean. Changing the balance between Daphnia and their predators marks a major change in lake systems.”

Republished courtesy of YFile– 91��ɫ’s daily e-bulletin.

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Published in the current issue of the , the study reports that despite guidelines encouraging physicians to recommend heart failure clinics, few patients recently hospitalized with heart failure receive referrals or use one.

“Given the demonstrated benefits of these services, the rates of referral and enrollment in our study are discouragingly low,” says lead investigator Shannon Gravely (PhD ’11) of 91��ɫ, the University Health Network and the Toronto Rehabilitation Institute. 91��ɫ Professor Sherry Grace and Professor Liane Ginsburg both of 91��ɫ’s Faculty of Health were also involved with the study.

Shannon Gravely

The investigators recruited 474 heart failure inpatients from 11 hospitals across Ontario. The patients completed a survey that evaluated environmental and individual factors affecting heart failure clinic use. Environmental factors included hospital type, whether the hospital had an onsite heart failure clinic and whether the patient had been referred to other outpatient disease management programs (DMP), such as smoking cessation clinics or diabetes education. Individual factors included socio-demographic information, whether the patient lived in a rural area, marital status, perceived stress and depressive symptoms. Clinical indicators of the need for rehabilitative services were gathered from patient charts.

A year after the first survey, the patients received a second survey. The 270 patients who completed the follow-up survey reported on whether they had been referred to a heart failure clinic and if they had attended.

Results showed that 15 per cent of study participants were referred to a heart failure clinic and 13 per cent reported using one. Patients with higher education were five times more likely to use an outpatient heart failure clinic compared to those with lower education. Lower stress levels and more serious health conditions were also associated with heart failure clinic use. Patients who received a referral to another DMP were nearly five times more likely to use a heart failure clinic. The most important factor in determining whether a patient used a heart failure clinic was the presence of an established program at the patient’s original hospital.

“It’s likely that having an HR clinic on-site is related to greater awareness of the benefits of such services by physicians providing care,” says Gravely. “However, broader referral mechanisms are needed to ensure that all patients, regardless of where they receive care, have equitable access to heart failure clinics.”

In a related study published in the same issue, Gravely and colleagues examined more broadly the use of DMPs by patients with cardiovascular disease (CVD). The survey looked at factors that influenced DMP use and was completed by 1,803 hospitalized patients, along with a follow-up study a year later which assessed whether they had used any DMPs, such as cardiac rehabilitation, outpatient diabetes education, a heart failure clinic, stroke rehabilitation or a smoking cessation program.

Overall, roughly 40 per cent of patients did not access any post-acute DMPs, 50 per cent accessed one program and 10 per cent attended more than one. Among participants with a comorbid indication (diabetes, stroke, heart failure or smokers), 21 per cent of these participants reported that they used multiple programs. DMP participants were younger, more likely to be married and more highly educated than those who did not attend DMPs.

Overall, 53 per cent reported participating in cardiac rehabilitation, and among participants with a comorbid illness or risk, 41per cent of diabetics reported attending a diabetes education center, 26 per cent of stroke patients attended stroke rehabilitation, 13 per cent of patients with a heart failure diagnosis used a heart failure clinic and 12 per cent of smokers attended a smoking cessation program. Among all study participants these findings suggest a gross underuse of DMP services, particularly stroke rehabilitation, heart failure clinics, and most notably, smoking cessation programs.

“What is one of the most concerning findings is that only 12 per cent of current smokers reported taking part in a smoking cessation program,” says Gravely. “Participation in smoking cessation programs results in significantly higher cessation rates when compared with standard care.”

Gravely notes that future research is needed to explore not only patient-related factors, but also health-system factors, such as awareness and capacity that may be at play. “The appropriateness and cost repercussions of multiple DMP use should be investigated, as an integrated approach to vascular disease management may be warranted.”

Republished courtesy of YFile– 91��ɫ’s daily e-bulletin.

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Many people overestimate the size of one serving of food as defined in Canada’s Food Guide, so they may be overeating even if they believe they are being careful, according to a study by Jennifer Kuk, a professor in the School of Kinesiology & Health Science in 91��ɫ’s Faculty of Health, and lead author Sharona Abramovitch, a former graduate student at 91��ɫ. The study was published online Tuesday in the journal .

Canada’s Food Guide is an important tool used by many general practitioners to help their patients eat more healthfully, says Kuk, so it made sense to study whether people would be able to tell from the food guide if they are eating enough of the four food groups: vegetables and fruit, meat and alternatives, grain products, and milk and alternatives.

Jennifer Kuk

“What we found was that the way people estimate one serving is essentially how much they would normally eat at one time,” says Kuk. “The majority of participants in the study inaccurately thought they would need to increase their food consumption by approximately 400 calories to meet recommendations in Canada’s Food Guide. This suggests we either need to change the size of a serving in the Guide – which has remained almost the same since 1977 – or educate Canadians more about how much food they should be consuming in a day.”

That eight-ounce steak you throw on the barbeque this summer, for example, alone exceeds the Canada Food Guide’s maximum daily allowance for meat and alternatives, says Abramovitch, a former graduate student in the School of Kinesiology & Health Science in 91��ɫ’s Faculty of Health. And only half a cup of cooked pasta is one of the eight grain servings allowed per day for a male between the ages of 19 and 50.

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Researchers analyzed food records from the 145 participants in the study, which included White, Black, South Asian and East Asian adults. They were asked to select what they thought was a serving, and researchers measured it to see whether the serving size corresponded with Canada’s Food Guide. They were also asked to estimate how much of something – for example, pasta – they would eat at one sitting, and to recall their diet over 24 hours.

All four ethnic groups inaccurately estimated the total number of servings they were eating in a day: they underestimated the number of servings of fruit and vegetables, grain products and meat, and overestimated the number of servings of milk and alternatives they were eating.

The research was funded by the Heart & Stroke Foundation.

Republished courtesy of YFile– 91��ɫ’s daily e-bulletin.

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The study, published this summer, examined the effects of exercises that build positivity on more than 250 participants. It found that people with needy personalities reported lower self-esteem after listening to three or four uplifting songs of their choosing every day over the course of a week.

Needy individuals suffer from deep insecurities and need interpersonal support to ward off acute feelings of despair and loneliness. They tend to be submissive in interpersonal relationships, feel helpless and fear abandonment.

“We were quite surprised at this result,” says study lead author Myriam Mongrain (right), professor of psychology in 91��ɫ’s Faculty of Health. “Until now, the vast majority of studies have suggested that positive psychology exercises result in either improvements for participants or no change over time. This result hints that self-help exercises may actually be detrimental for those with needy personalities,” she says.

Study participants were randomly assigned one of three daily exercises: recalling five things that they were grateful for over the course of the day; listening to three or four uplifting songs of their choosing; or writing about a specific memory from their early life (the latter was used as a control exercise). Participants then completed questionnaires to measure changes in their mood and outlook; these same measures were administered at intervals of one, three and six months post-study.

Those with needy personalities reported no significant benefits from the gratitude exercise, while the music exercise dragged them down further. Highly self-critical individuals experienced the greatest improvement to their subjective happiness when they practiced the gratitude exercise. They also demonstrated a larger increase in self-esteem and greater decrease in physical symptom severity in both the gratitude condition and the music condition.

“We hypothesized that listening to happy music was a kind of self-soothing that would benefit people with needy personalities. However, this independent activity, which involved no interaction with others, may have had a negative effect on participants,” says Mongrain.

“Needy people rely on secure intimate bonds with others in order to experience well-being, and they may have felt frustrated with the lack of improvement and expressed their disappointment on the outcome measures. Given these results, one-on-one counselling is likely more appropriate for this personality type.”

The study was published in August 2011 in the Journal of Positive Psychology. It is co-authored by Susan Sergeant, a PhD student in 91��ɫ’s Department of Psychology.

Republished courtesy of YFile– 91��ɫ’s daily e-bulletin.

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