Scientific Writing, HRP 214 Weekly Quiz

1
Scientific Writing, HRP 214Weekly Quiz
2
Scientific Writing, HRP 214Weekly Quiz

• A. It was a secret among friends.
• B. It was a secret between friends.

3
Scientific Writing, HRP 214Weekly Quiz

• A. It was a secret among friends.
• B. It was a secret between friends.

4
Scientific Writing, HRP 214Weekly Quiz

• A. The close friendship that existed between
  them was quickly dissolved.
• B. The close friendship that existed among them
  was quickly dissolved.

5
Scientific Writing, HRP 214Weekly Quiz

• A. The close friendship that existed between
  them was quickly dissolved.
• B. The close friendship that existed among them
  was quickly dissolved.

6
Scientific Writing, HRP 214 Weekly Quiz

• A. She eluded to the fight that occurred earlier.
• B. She alluded to the the fight that occurred
  earlier.

7
Scientific Writing, HRP 214 Weekly Quiz

• A. She eluded to the fight that occurred earlier.
• B. She alluded to the the fight that occurred
  earlier.

8
Scientific Writing, HRP 214 Weekly Quiz

• A. She eluded the fight.
• B. She alluded the fight.

9
Scientific Writing, HRP 214 Weekly Quiz

• A. She eluded the fight.
• B. She alluded the fight.

10
Scientific Writing, HRP 214Weekly Quiz

• A. She lies out in the sun.
• B. She lays out in the sun.

11
Scientific Writing, HRP 214Weekly Quiz

• A. She lies out in the sun.
• B. She lays out in the sun.

12
Scientific Writing, HRP 214Weekly Quiz

• A. She is lying out in the sun.
• B. She is laying out in the sun.

13
Scientific Writing, HRP 214Weekly Quiz

• A. She is lying out in the sun.
• B. She is laying out in the sun.

14
Scientific Writing, HRP 214Weekly Quiz

• A. She laid out in the sun yesterday.
• B. She lay out in the sun yesterday.

15
Scientific Writing, HRP 214Weekly Quiz

• A. She laid out in the sun yesterday.
• B. She lay out in the sun yesterday.

16
Scientific Writing, HRP 214Weekly Quiz

• A. She had laid out in the sun too much as a kid.
• B. She had lain out in the sun too much as a kid.

17
Scientific Writing, HRP 214Weekly Quiz

• A. She had laid out in the sun too much as a kid.
• B. She had lain out in the sun too much as a kid.

18
Scientific Writing, HRP 214Weekly Quiz

• A. She lies the book on the table.
• B. She lays the book on the table.

19
Scientific Writing, HRP 214Weekly Quiz

• A. She lies the book on the table.
• B. She lays the book on the table.

20
Scientific Writing, HRP 214Weekly Quiz

• A. She is lying the book on the table.
• B. She is laying the book on the table.

21
Scientific Writing, HRP 214Weekly Quiz

• A. She is lying the book on the table.
• B. She is laying the book on the table.

22
Scientific Writing, HRP 214Weekly Quiz

• A. She laid the book on the table this morning.
• B. She lay the book on the table this morning.

23
Scientific Writing, HRP 214Weekly Quiz

• A. She laid the book on the table this morning.
• B. She lay the book on the table this morning.

24
Scientific Writing, HRP 214Weekly Quiz

• A. She had lain the book on the table.
• B. She had laid the book on the table.

25
Scientific Writing, HRP 214Weekly Quiz

• A. She had lain the book on the table.
• B. She had laid the book on the table.

26
Scientific Writing, HRP 214Weekly Quiz

• A. Now I lay down to sleep.
• B. Now I lie down to sleep.

27
Scientific Writing, HRP 214Weekly Quiz

• A. Now I lay down to sleep.
• B. Now I lie down to sleep.

28
Scientific Writing, HRP 214Weekly Quiz

• A. Now I lay me down to sleep.
• B. Now I lie me down to sleep.

29
Scientific Writing, HRP 214Weekly Quiz

• A. Now I lay me down to sleep.
• B. Now I lie me down to sleep.

30
Scientific Writing, HRP 214Weekly Quiz

• A. I am disinterested in your results.
• B. I am uninterested in your results.

31
Scientific Writing, HRP 214Weekly Quiz

• A. I am disinterested in your results.
• B. I am uninterested in your results.

32
Scientific Writing, HRP 214 Weekly Quiz

• A. We think you should look into an alternative
  career path, i.e. get a new job.
• B. We think you should look into an alternative
  career path, e.g. get a new job.

33
Scientific Writing, HRP 214 Weekly Quiz

• A. We think you should look into an alternative
  career path, i.e. get a new job.
• B. We think you should look into an alternative
  career path, e.g. get a new job.

34
Scientific Writing, HRP 214 Weekly Quiz

• A. They prefer mixed drinks, e.g. gin and tonic
  or martinis.
• B. They prefer mixed drinks, i.e. gin and tonic
  or martinis.

35
Scientific Writing, HRP 214 Weekly Quiz

• A. They prefer mixed drinks, e.g. gin and tonic
  or martinis.
• B. They prefer mixed drinks, i.e. gin and tonic
  or martinis.

36
Scientific Writing, HRP 214 Weekly Quiz

• She served as a disinterested party in the
  dispute.
• She served as an uninterested party in the
  dispute.

37
Scientific Writing, HRP 214 Weekly Quiz

• She served as a disinterested party in the
  dispute.
• She served as an uninterested party in the
  dispute.

38
Scientific Writing, HRP 214 Weekly Quiz

• A. You should eat more sweets, e.g. chocolate.
• B. You should eat more sweets, i.e. chocolate.

39
Scientific Writing, HRP 214 Weekly Quiz

• A. You should eat more sweets, e.g. chocolate.
• B. You should eat more sweets, i.e. chocolate.

40
Scientific Writing, HRP 214

• Lecture 6 July 27, 2005
• The Abstract, Introduction, and Discussion

41
Scientific Writing, HRP 214Abstracts

• Abstracts (about, traherepull to pull out)
• Overview of the main story
• Gives highlights from each section of the paper
• Limited length (100-300 words, typically)
• Stands on its own
• Used, with title, for electronic search engines
• Most often, the only part people read

42
Scientific Writing, HRP 214Abstracts

• Gives
• Background
• Question asked
• We asked whether, We hypothesized that,etc.
• Experiment(s) done
• Material studied (molecule, cell line, tissue,
  organ) or the animal or human population studied
• The experimental approach or study design and the
  independent and dependent variables
• Results found
• Key results found
• Minimal raw data (prefer summaries)
• The answer to the question asked
• Implication, speculation, or recommendation

43
Scientific Writing, HRP 214Abstracts

• Abstracts may be structured (with subheadings) or
  free-form.

44
Scientific Writing, HRP 214Abstracts

• Structured example (The Lancet, May 7, 2003)
• Epidemiological determinants of spread of causal
  agent of severe acute respiratory syndrome in
  Hong Kong
• Christl A Donnelly, Azra C Ghani, Gabriel M
  Leung, Anthony J Hedley, Christophe Fraser,
  Steven Riley, Laith J Abu-Raddad, Lai-Ming Ho,
  Thuan-Quoc Thach, Patsy Chau, King-Pan Chan,
  Tai-Hing Lam, Lai-Yin Tse, Thomas Tsang,
  Shao-Haei Liu, James H B Kong, Edith M C Lau,
  Neil M Ferguson, Roy M Anderson

45
Scientific Writing, HRP 214Abstracts

• Background
• Health authorities worldwide, especially in the
  Asia Pacific region, are seeking effective
  public-health interventions in the continuing
  epidemic of severe acute respiratory syndrome
  (SARS). We assessed the epidemiology of SARS in
  Hong Kong.
• Methods
• We included 1425 cases reported up to April 28,
  2003. An integrated database was constructed from
  several sources containing information on
  epidemiological, demographic, and clinical
  variables. We estimated the key epidemiological
  distributions infection to onset, onset to
  admission, admission to death, and admission to
  discharge. We measured associations between the
  estimated case fatality rate and patients' age
  and the time from onset to admission.

46
Scientific Writing, HRP 214Abstracts

• Findings
• After the initial phase of exponential growth,
  the rate of confirmed cases fell to less than 20
  per day by April 28. Public-health interventions
  included encouragement to report to hospital
  rapidly after the onset of clinical symptoms,
  contact tracing for confirmed and suspected
  cases, and quarantining, monitoring, and
  restricting the travel of contacts. The mean
  incubation period of the disease is estimated to
  be 64 days (95 CI 52-77). The mean time from
  onset of clinical symptoms to admission to
  hospital varied between 3 and 5 days, with longer
  times earlier in the epidemic. The estimated case
  fatality rate was 132 (98-168) for patients
  younger than 60 years and 433 (352-524) for
  patients aged 60 years or older assuming a
  parametric g distribution. A non-parametric
  method yielded estimates of 68 (40-96) and
  550 (453-647), respectively. Case clusters
  have played an important part in the course of
  the epidemic.
• Interpretation
• Patients' age was strongly associated with
  outcome. The time between onset of symptoms and
  admission to hospital did not alter outcome, but
  shorter intervals will be important to the wider
  population by restricting the infectious period
  before patients are placed in quarantine.

47
Scientific Writing, HRP 214Abstracts

• Structured example 2
• Binge Eating as a Major Phenotype of Melanocortin
  4 Receptor Gene Mutation
• New England Journal of Medicine Volume
  3481096-1103 March 20, 2003
• Ruth Branson, M.B., Ch.B., Natascha Potoczna,
  M.D., John G. Kral, M.D., Ph.D., Klaus-Ulrich
  Lentes, Ph.D., Margret R. Hoehe, M.D., Ph.D., and
  Fritz F. Horber, M.D.  

48
Scientific Writing, HRP 214Abstracts

• ABSTRACT
• Background
• Obesity, a multifactorial disease caused by the
  interaction of genetic factors with the
  environment, is largely polygenic. A few
  mutations in these genes, such as in the leptin
  receptor (LEPR) gene and melanocortin 4 receptor
  (MC4R) gene, have been identified as causes of
  monogenic obesity.
• Methods
• We sequenced the complete MC4R coding region,
  the region of the proopiomelanocortin gene (POMC)
  encoding the melanocyte-stimulating hormone, and
  the leptin-binding domain of LEPR in 469 severely
  obese white subjects (370 women and 99 men mean
  SE age, 41.00.5 years body-mass index the
  weight in kilograms divided by the square of the
  height in meters, 44.12.0). Fifteen women and
  10 men without a history of dieting or a family
  history of obesity served as normal-weight
  controls (age, 47.72.0 years body-mass index,
  21.60.4). Detailed phenotypic data, including
  information on body fat, resting energy
  expenditure, diet-induced thermogenesis, serum
  concentrations of leptin, and eating behavior,
  were collected.

49
Scientific Writing, HRP 214Abstracts

• Results
• Twenty-four obese subjects (5.1 percent) and one
  control subject (4 percent) had MC4R mutations,
  including five novel variants. Twenty of the 24
  obese subjects with an MC4R mutation were matched
  for age, sex, and body-mass index with 120 of the
  445 obese subjects without an MC4R mutation. All
  mutation carriers reported binge eating, as
  compared with 14.2 percent of obese subjects
  without mutations (Pnormal-weight subjects without mutations. The
  prevalence of binge eating was similar among
  carriers of mutations in the leptin-binding
  domain of LEPR and noncarriers. No mutations were
  found in the region of POMC encoding
  melanocyte-stimulating hormone.
• Conclusions
• Binge eating is a major phenotypic
  characteristic of subjects with a mutation in
  MC4R, a candidate gene for the control of eating
  behavior.

50
Scientific Writing, HRP 214Abstracts

• Even more subheadings
• Lung Cancer Screening With Helical Computed
  Tomography in Older Adult Smokers A Decision and
  Cost-effectiveness Analysis
• Parthiv J. Mahadevia, MD, MPH Lee A. Fleisher,
  MD Kevin D. Frick, PhD John Eng, MD Steven N.
  Goodman, MD, PhD Neil R. Powe, MD, MPH, MBA
• JAMA. 2003289313-322.

51
Scientific Writing, HRP 214Abstracts

• Context 
• Encouraged by direct-to-consumer marketing,
  smokers and their physicians are contemplating
  lung cancer screening with a promising but
  unproven imaging procedure, helical computed
  tomography (CT).
• Objective 
• To estimate the potential benefits, harms, and
  cost-effectiveness of lung cancer screening with
  helical CT in various efficacy scenarios.
• Design, Setting, and Population 
• Using a computer-simulated model, we compared
  annual helical CT screening to no screening for
  hypothetical cohorts of 100 000 current,
  quitting, and former heavy smokers, aged 60
  years, of whom 55 were men. We simulated
  efficacy by changing the clinical stage
  distribution of lung cancers so that the screened
  group would have fewer advanced-stage cancers and
  more localized-stage cancers than the nonscreened
  group (ie, a stage shift). Our model incorporated
  known biases in screening programs such as lead
  time, length, and overdiagnosis bias.

52
Scientific Writing, HRP 214Abstracts

• Main Outcome Measures 
• We measured the benefits of screening by
  comparing the absolute and relative difference in
  lung cancerspecific deaths. We measured harms by
  the number of false-positive invasive tests or
  surgeries per 100 000 and incremental
  cost-effectiveness in US dollars per
  quality-adjusted life-year (QALY) gained.
• Results 
• Over a 20-year period, assuming a 50 stage
  shift, the current heavy smoker cohort had 553
  fewer lung cancer deaths (13 lung
  cancerspecific mortality reduction) and 1186
  false-positive invasive procedures per 100 000
  persons. The incremental cost-effectiveness for
  current smokers was 116 300 per QALY gained. For
  quitting and former smokers, the incremental
  cost-effectiveness was 558 600 and 2 322 700
  per QALY gained, respectively. Other than the
  degree of stage shift, the most influential
  parameters were adherence to screening, degree of
  length or overdiagnosis bias in the first year of
  screening, quality of life of persons with
  screen-detected localized lung cancers, cost of
  helical CT, and anxiety about indeterminate
  nodule diagnoses. In 1-way sensitivity analyses,
  none of these parameters was sufficient to make
  screening highly cost-effective for any of the
  cohorts. In multiway sensitivity analyses, a
  program screening current smokers was 42 500 per
  QALY gained if extremely favorable estimates were
  used for all of the influential parameters
  simultaneously.

53
Scientific Writing, HRP 214Abstracts

• Conclusion 
• Even if efficacy is eventually proven, screening
  must overcome multiple additional barriers to be
  highly cost-effective. Given the current
  uncertainty of benefits, the harms from invasive
  testing, and the high costs associated with
  screening, direct-to-consumer marketing of
  helical CT is not advisable.

54
Scientific Writing, HRP 214Abstracts

• Science Volume 300, Number 5620, 2 May 2003,
  pp. 786-789.
• The Potential for Earthquake Early Warning in
  Southern California
• Richard M. Allen1 and Hiroo Kanamori2
• Earthquake mitigation efforts in the United
  States currently use long-term probabilistic
  hazard assessments and rapid post-earthquake
  notification to reduce the potential damage of
  earthquakes. Here we present the seismological
  design for and demonstrate the feasibility of a
  short-term hazard warning system. Using data from
  past earthquakes, we show that our Earthquake
  Alarm System (ElarmS) could, with current TriNet
  instrumentation, issue a warning a few to tens of
  seconds ahead of damaging ground motion. The
  system uses the frequency content of the P-wave
  arrival to determine earthquake magnitude, an
  approach that allows magnitude determination
  before any damaging ground motion occurs.

55
Scientific Writing, HRP 214Introduction and
Background

• Introduction and Background Section

56
Scientific Writing, HRP 214Introduction and
Background

• The Literature Search
• Utilize online databases, such as MEDLINE,
  PubMed, and Ovid.
• Have a search strategy.
• Have an organizational system!

57
Scientific Writing, HRP 214Introduction and
Background

• The Literature Review
• Summarize the current state of knowledge in the
  area of investigation.
• You may have to return to the literature once
  your results are in hand.
• Assume your reader is knowledgeable about the
  field.
• Do not provide an exhaustive historical review.
• Avoid nonessential details.
• Summarize previous results and conclusions, but
  do not give the methods that generated these
  findings unless they are relevant to your
  research question (i.e., your experiment
  addresses a specific methodologic limitation of
  previous experiments)
• Refer the reader to general surveys or reviews of
  the topic if available.
• Cite references that reflect the key work that
  led to your research question.
• Limit the number of references.

58
Scientific Writing, HRP 214

• In writing the literature review, summarize
  rather than listing every possible reference and
  example.

59
Scientific Writing, HRP 214Introduction and
Background

• Introduction and Background
• 1. Whats known
• 2. Whats unknown
• limitations and gaps in previous studies
• 3. Your burning question
• 4. Your experimental approach
• 5. Why your experimental approach is new and
  different and important

60
Scientific Writing, HRP 214Introduction

• Tell a story
• Write it in plain English, not tech-speak.
• Take the reader step by step from what is known
  to what is unknown. End with your specific
  question.
• (Known?Unknown?Question)
• Emphasize what is new and important about your
  work.
• Do not state the answer to the research question.
• Do not include results or implications.

61
Introduction

• Overweight, Obesity, and Mortality from Cancer in
  a Prospectively Studied Cohort of U.S.
  AdultsEugenia E. Calle, Ph.D., Carmen Rodriguez,
  M.D., M.P.H., Kimberly Walker-Thurmond, B.A., and
  Michael J. Thun, M.D.  

62

• The relations between excess body weight and
  mortality, not only from all causes but also from
  cardiovascular disease, are well
  established.1,2,3,4,5,6 Although we have known
  for some time that excess weight is also an
  important factor in death from cancer,7 our
  knowledge of the magnitude of the relation, both
  for all cancers and for cancers at individual
  sites, and the public health effect of excess
  weight in terms of total mortality from cancer is
  limited. Previous studies have consistently shown
  associations between adiposity and increased risk
  of cancers of the endometrium, kidney,
  gallbladder (in women), breast (in postmenopausal
  women), and colon (particularly in
  men).8,9,10,11,12 Adenocarcinoma of the esophagus
  has been linked to obesity.11,13,14 Data on
  cancers of the pancreas, prostate, liver, cervix,
  and ovary and on hematopoietic cancers are scarce
  or inconsistent.7,8,9,10,11,15,16,17 The lack of
  consistency may be attributable to the limited
  number of studies (especially those with
  prospective cohorts), the limited range and
  variable categorization of overweight and obesity
  among studies, bias introduced by reverse
  causality with respect to smoking-related
  cancers, and possibly real differences between
  the effects of overweight and obesity on the
  incidence of cancer and on the rates of death
  from some cancers.18,19
• We conducted a prospective investigation in a
  large cohort of U.S. men and women to determine
  the relations between body-mass index (the weight
  in kilograms divided by the square of the height
  in meters) and the risk of death from cancer at
  specific sites. This cohort has been used
  previously to examine the association of
  body-mass index and death from any cause.5

63
Scientific Writing, HRP 214

• Introduction
• Exogenous estrogens prevent or substantially
  retard the decrease in bone mineral density (BMD)
  that accompanies menopause 1. However, it is
  unclear whether exogenous estrogens, administered
  as oral contraceptives (OCs), can modify
  premenopausal BMD. Several studies suggest that
  exposure to OCs during the premenopausal years
  has a favorable effect on BMD 2-10, whereas
  other studies show no effect 11-18.
• Past studies of the relationship between OC use
  and BMD have several limitations. Studies have
  focused primarily on crude measures of OC use,
  such as current, past and never. These
  categories combine diverse types of OC use and
  may reduce the power to detect an effect. Many
  studies also failed to take into account
  lifestyle characteristics of study participants.
  Finally, few studies have considered an effect of
  OCs on BMD in women of races other than white.
• The aim of this study was to evaluate the
  associations of OCs with spine, hip and whole
  body BMD in black and white premenopausal women.
  Our primary hypothesis was that there would be an
  association between cumulative exposure to
  estrogen from OCs and BMD.

64
Scientific Writing, HRP 214

• Neurohumoral Features of Myocardial Stunning Due
  to Sudden Emotional StressIlan S. Wittstein,
  M.D., David R. Thiemann, M.D., Joao A.C. Lima,
  M.D., Kenneth L. Baughman, M.D., Steven P.
  Schulman, M.D., Gary Gerstenblith, M.D.,
  Katherine C. Wu, M.D., Jeffrey J. Rade, M.D.,
  Trinity J. Bivalacqua, M.D., Ph.D., and Hunter C.
  Champion, M.D., Ph.D. T
• New Engl J Med Volume 352539-548 Feb 10, 2005.

65
Scientific Writing, HRP 214

• The potentially lethal consequences of emotional
  stress are deeply rooted in folk wisdom, as
  reflected by phrases such as "scared to death"
  and "a broken heart." In the past decade, cardiac
  contractile abnormalities and heart failure have
  been reported after acute emotional
  stress,1,2,3,4,5,6 but the mechanism remains
  unknown. We evaluated 19 patients with "stress
  cardiomyopathy," a syndrome of profound
  myocardial stunning precipitated by acute
  emotional stress, in an effort to identify the
  clinical features that distinguish this syndrome
  from acute myocardial infarction and the cause of
  transient stress-induced myocardial dysfunction.

66
Introduction cost-effectiveness study

• Cost-Effectiveness of Screening for HIV in the
  Era of Highly Active Antiretroviral
  TherapyGillian D. Sanders, Ph.D., Ahmed M.
  Bayoumi, M.D., Vandana Sundaram, M.P.H., S. Pinar
  Bilir, A.B., Christopher P. Neukermans, A.B.,
  Chara E. Rydzak, B.A., Lena R. Douglass, B.S.,
  Laura C. Lazzeroni, Ph.D., Mark Holodniy, M.D.,
  and Douglas K. Owens, M.D.
• New Engl J Med Volume 352 570-585 Feb 10,
  2005.

67
Introduction

• Timely identification of human immunodeficiency
  virus (HIV) infection is critical from both
  clinical and public health perspectives. A delay
  in diagnosis until late in the course of HIV
  infection may be associated with irreversible
  immunologic damage and related complications.
  Early identification also provides the
  opportunity to reduce transmission of HIV through
  changes in risk behavior.1,2,3 Treatment with
  highly active antiretroviral therapy (HAART) most
  likely reduces infectivity4 and may therefore
  afford an additional public health benefit by
  further reducing transmission. Despite these
  compelling reasons for early identification, the
  Centers for Disease Control and Prevention (CDC)
  estimate that up to 20,000 new HIV infections
  annually can be attributed to people who are
  unaware of their HIV-positive status. Such people
  represent up to 280,000 of the approximately
  950,000 people infected with HIV in the United
  States.5 CDC data indicate that in 41 percent of
  HIV-positive patients, the acquired
  immunodeficiency syndrome (AIDS) develops within
  a year after they received the diagnosis,6
  suggesting that opportunities for preventing
  adverse outcomes were missed.

Background/relevance whats known about the
potential merits of screening and early detection
68
Introduction, continued

• A fundamental strategy of a new CDC initiative to
  promote early identification of HIV disease is to
  make voluntary HIV testing a routine part of
  medical care.7,8 Although we and others
  previously evaluated the cost-effectiveness of
  screening,9,10,11,12 these analyses were
  performed before HAART became available. Because
  both the costs and the benefits of screening have
  changed since these analyses were published, the
  current cost-effectiveness of screening and the
  settings in which screening is economically
  attractive remain uncertain. We sought to
  evaluate the cost-effectiveness of voluntary HIV
  screening in health care settings and to assess
  how incorporating the costs and benefits
  associated with reductions in HIV transmission
  would influence the cost-effectiveness of a
  screening program.

69
Introduction systematic review

• Effectiveness of speed cameras in preventing
  road traffic collisions and related casualties
  systematic review
• Paul Pilkington, lecturer in public health1,
  Sanjay Kinra, lecturer in epidemiology and public
  health medicine2 1 University of the West of
  England, Faculty of Health and Social Care,
  Bristol BS16 1DD, 2 Department of Social
  Medicine, University of Bristol, Bristol .
• BMJ Feb. 10, 2005

70

• Road traffic collisions are an important cause
  of death and disability worldwide. Every year
  around the world 1.2 million people are killed
  and up to 50 million are injured or disabled as a
  result of road traffic collisions.1 Morbidity
  from road traffic collisions is expected to
  increase in future years, and it is estimated
  that road traffic collisions will move from ninth
  to third place in the global burden of disease
  ranking, as measured in disability adjusted life
  years.2 3
• Measures to reduce traffic speed are considered
  essential to reducing casualties on the road.1 4
  5 Speed cameras are increasingly used to help to
  reduce traffic speeds in the belief that this
  will reduce road traffic collisions and
  casualties, and an expansion in the use of speed
  cameras is under way in many countries, most
  notably the United Kingdom.6 The use of speed
  cameras is controversial, however. Vociferous
  opponents, including some motoring associated
  organisations, oppose their use, and cameras are
  often criticised in the media.7-9 The lack of
  readily available evidence of the effectiveness
  of cameras has made it difficult for road safety
  and health professionals to engage in an informed
  debate about the effectiveness of speed cameras.
• A previous small non-systematic review of six
  studies found a 17 reduction in collisions after
  introduction of speed cameras.10 Non-systematic
  reviews can, however, be limited by bias. We
  aimed, therefore, to systematically assess the
  evidence for the effectiveness of speed cameras
  in reducing road traffic collisions and related
  casualties.

71
Scientific Writing, HRP 214Introduction and
Background

• Introduction and Background
• 1. Whats known
• 2. Whats unknown
• limitations and gaps in previous studies
• 3. Your burning question
• 4. Your experimental approach
• 5. Why your experimental approach is new and
  different and important

72
Scientific Writing, HRP 214Introduction

• Tell a story
• Write it in plain English, not tech-speak.
• Take the reader step by step from what is known
  to what is unknown. End with your specific
  question.
• (Known?Unknown?Question)
• Emphasize what is new and important about your
  work.
• Do not state the answer to the research question.
• Do not include results or implications.

73
Scientific Writing, HRP 214THE DISCUSSION

• The Discussion is the section that
• Gives you the most freedom
• Gives you the most chance to put good writing on
  display
• Is the most challenging to write

74
Scientific Writing, HRP 214The Discussion

• Follow your rules for good writing!

75
Scientific Writing, HRP 214The Discussion

• The purpose of the discussion
• Answer the question posed in the Introduction
• Support your conclusion with details (yours,
  others)
• Defend your conclusion (acknowledge limits)
• Highlight the broader implications of the work
• i.e., What do my results mean and why should
  anyone care?

76
Framework of the Discussion
Table 2, Adapted From Welch HG. Preparing
Manuscripts for Submission to Medical Journals
The Paper Trail. Effective Clinical Practice.
1999 2 131-137.
77
Scientific Writing, HRP 214The Discussion

• The introduction moves from general to specific.
  
• The discussion moves from specific to general.

78
Scientific Writing, HRP 214The Discussion

• Elements of the typical discussion section

79

• Key finding (answer to the question(s) asked in
  Intro.)
• Supporting explanation, details (lines of
  evidence)
• Possible mechanisms or pathways
• Is this finding novel?
• Key secondary findings
• Context
• Compare your results with other peoples results
• Compare your results with existing paradigms
• Explain unexpected or surprising findings
• Strengths and limitations
• Whats next
• Recommended confirmatory studies (needs to be
  confirmed)
• Unanswered questions
• Future directions
• The so what? implicate, speculate, recommend
• Clinical implications of basic science findings
• Strong conclusion (kicker!)

80
EXAMPLE Samaha FF, Iqbal N, Seshadri P, et al.
A low-carbohydrate as compared with a low-fat
diet in severe obesity. N Engl J Med
20033482074-2081.

• INTRODUCTION
• The differences in health benefits between a
  carbohydrate-restricted diet and a calorie- and
  fat-restricted diet are of considerable public
  interest. However, there is concern that a
  carbohydrate-restricted diet will adversely
  affect serum lipid concentrations.1 Previous
  studies demonstrating that healthy volunteers
  following a low-carbohydrate diet can lose weight
  have involved few subjects, and few used a
  comparison group that followed consensus
  guidelines for weight loss.2,3 The reported
  effects of a carbohydrate-restricted diet on risk
  factors for atherosclerosis have varied.2,3,4 We
  performed a study designed to test the hypothesis
  that severely obese subjects with a high
  prevalence of diabetes or the metabolic syndrome
  a would have a greater weight loss, b without
  detrimental effects on risk factors for
  atherosclerosis, while on a carbohydrate-restricte
  d (low-carbohydrate) diet than on a calorie- and
  fat-restricted (low-fat) diet.

81
Scientific Writing, HRP 214The Discussion

• 1. We found that severely obese subjects with a
  high prevalence of diabetes and the metabolic
  syndrome lost more weight in a six-month period
  on a carbohydrate-restricted diet than on a fat-
  and calorie-restricted diet. answer to a The
  greater weight loss in the low-carbohydrate group
  suggests a greater reduction in overall caloric
  intake, rather than a direct effect of
  macronutrient composition. mechanisms However,
  the explanation for this difference is not clear.
  Subjects in this group may have experienced
  greater satiety on a diet with liberal
  proportions of protein and fat. However, other
  potential explanations include the simplicity of
  the diet and improved compliance related to the
  novelty of the diet. possible mechanisms/unanswer
  ed questions

82
Scientific Writing, HRP 214The Discussion

• 2. Subjects in the low-carbohydrate group had
  greater decreases in triglyceride levels than did
  subjects in the low-fat group nondiabetic
  subjects on the low-carbohydrate diet had greater
  increases in insulin sensitivity, and subjects
  with diabetes on this diet had a greater
  improvement in glycemic control. No adverse
  effects on other serum lipid levels were
  observed. answer to b Most studies suggest that
  lowering triglyceride levels has an overall
  cardiovascular benefit.14,15,16 Insulin
  resistance promotes such atherosclerotic
  processes as inflammation,17 decreased size of
  low-density lipoprotein particles,18 and
  endothelial dysfunction.19 Impaired glycemic
  control in subjects with other features of the
  metabolic syndrome markedly increases the risk of
  coronary artery disease.20 As expected, we found
  that the amount of weight lost had a significant
  effect on the degree of improvement in these
  metabolic factors. comparison to previous
  studies and paradigms However, even after
  adjustment for the differences in weight loss
  between the groups, assignment to the
  low-carbohydrate diet predicted greater
  improvements in triglyceride levels and insulin
  sensitivity. unexpected Subjects who lost more
  than 5 percent of their base-line weight on a
  carbohydrate-restricted diet had greater
  decreases in triglyceride levels than those who
  lost a similar amount of weight while following a
  calorie- and fat-restricted diet. supporting
  details

83
Scientific Writing, HRP 214The Discussion

• 3. There was a consistent trend across
  weight-loss strata toward a greater increase in
  insulin sensitivity in the low-carbohydrate
  group, although these changes were small and were
  not significant within each stratum. supporting
  details dose/response Although greater weight
  loss could not entirely account for the greater
  decrease in triglyceride levels and increase in
  insulin sensitivity in the low-carbohydrate
  group, we cannot definitively conclude that
  carbohydrate restriction alone accounted for this
  independent effect. mechanisms Other
  uncontrolled variables, such as the types of
  carbohydrates selected (e.g., the proportion of
  complex carbohydrates or the ratio of
  carbohydrate to fiber), or other unknown
  variables may have contributed to this effect. In
  addition, more precise measurements of insulin
  sensitivity than we used would be needed to
  confirm this effect of a carbohydrate-restricted
  diet. limitations/future studies

84
Scientific Writing, HRP 214The Discussion

• 4. Many of our subjects were taking
  lipid-lowering medications and hypoglycemic
  agents. Although enrolling these subjects
  introduced confounding variables, it allowed the
  inclusion of subjects with the obesity-related
  medical disorders typically encountered in
  clinical practice. Analyses from which these
  subjects were excluded still revealed greater
  improvements in insulin sensitivity and
  triglyceride levels on a carbohydrate-restricted
  diet than on a fat- and calorie-restricted diet.
  limitations and how they were addressed

85
Scientific Writing, HRP 214The Discussion

• 5. Our study included a high proportion of black
  subjects, a group previously underrepresented in
  lifestyle-modification studies. strength As
  compared with the white subjects, the black
  subjects had a smaller overall weight loss.
  Future studies should explore whether greater
  weight loss in this population can be achieved by
  more effective incorporation of culturally
  sensitive dietary counseling. future directions
• 6. The high dropout rate in our study occurred
  very early and affected our findings. The very
  early dropout of these subjects may indicate that
  attrition most closely reflected base-line
  motivation to lose weight, rather than a response
  to the dietary intervention itself. limitation

86
Scientific Writing, HRP 214The Discussion

• 7. Taken together, our findings demonstrate that
  severely obese subjects with a high prevalence of
  diabetes and the metabolic syndrome lost more
  weight during six months on a carbohydrate-restric
  ted diet than on a calorie- and fat-restricted
  diet. The carbohydrate-restricted diet led to
  greater improvements in insulin sensitivity that
  were independent of weight loss and a greater
  reduction in triglyceride levels in subjects who
  lost more than 5 percent of their base-line
  weight. conclusion restate answers to a and b
  These findings must be interpreted with caution,
  however, since the magnitude of the overall
  weight loss relative to our subjects' severe
  obesity was small, and it is unclear whether
  these benefits of a carbohydrate-restricted diet
  extend beyond six months. Furthermore, the high
  dropout rate and the small overall weight loss
  demonstrate that dietary adherence was relatively
  low in both diet groups. big picture This study
  proves a principle and does not provide clinical
  guidance given the known benefits of fat
  restriction, future studies evaluating long-term
  cardiovascular outcomes are needed before a
  carbohydrate-restricted diet can be endorsed.
  take-home message

87
Scientific Writing, HRP 214The Discussion

• Things to avoid in the discussion
• Do not simply repeat what is in the Results
• Do not try to explain every minor flaw
• Do not attempt to explain away every unexpected
  result
• Do not exaggerate or make extravagant claims
• Dont hedge

88
Scientific Writing, HRP 214The Discussion verb
tense

• Verb Tenses (active!)
• Past, when referring to study details, results,
  analyses, and background research
• We found that
• They lost more weight than
• Subjects may have experienced
• Miller et al. found
• Present, when talking about what the data suggest
  
• The greater weight loss suggests
• The explanation for this difference is not
  clear.
• Potential explanations include

89
Scientific Writing, HRP 214The Discussion

• Example 2
• Nature 423, 409 - 414 (2003) doi10.1038/nature01
  593 The HSC (Haematopoietic stem cells) has the
  ability to perpetuate itself as well as to
  differentiate into mature blood cells of all
  lineages. In the mouse, long-term self-renewing
  HSCs make up approximately 0.007 of bone marrow
  and can be isolated by their expression of
  undetectable levels of lineage markers (such as
  B220, CD3, Mac-1), high levels of c-Kit and
  Sca-1, and low levels of Thy-1 (refs 1, 2).
  Although HSCs have been purified successfully and
  their phenotypic and functional properties well
  characterized1-4, a fundamental question that
  remains is how their self-renewing growth is
  regulated. On the basis of a screen of genes
  expressed in HSCswhere we noted that members of
  the LEF-1/TCF family were expressed (K. Li, S.
  Cheshier and I.L.W., unpublished data)and our
  previous finding that Wnt signalling can
  influence lymphocyte progenitor cell
  proliferation5, we have investigated whether Wnt
  signalling influences HSC development.

90
Scientific Writing, HRP 214The Discussion

• Example 2
• Nature 423, 409 - 414 (2003) doi10.1038/nature01
  593 The HSC (Haematopoietic stem cells) has the
  ability to perpetuate itself as well as to
  differentiate into mature blood cells of all
  lineages. In the mouse, long-term self-renewing
  HSCs make up approximately 0.007 of bone marrow
  and can be isolated by their expression of
  undetectable levels of lineage markers (such as
  B220, CD3, Mac-1), high levels of c-Kit and
  Sca-1, and low levels of Thy-1 (refs 1, 2).
  Although HSCs have been purified successfully and
  their phenotypic and functional properties well
  characterized1-4, a fundamental question that
  remains is how their self-renewing growth is
  regulated. On the basis of a screen of genes
  expressed in HSCswhere we noted that members of
  the LEF-1/TCF family were expressed (K. Li, S.
  Cheshier and I.L.W., unpublished data)and our
  previous finding that Wnt signalling can
  influence lymphocyte progenitor cell
  proliferation5, we have investigated whether Wnt
  signalling influences HSC development.

91

• DiscussionOur study shows that components of
  the Wnt signalling pathway can induce
  proliferation of purified KTLS bone marrow HSCs
  while significantly inhibiting their
  differentiation, thereby resulting in functional
  self-renewal. ANSWER TO THE QUESTION ASKED We
  find that expression of -catenin in HSCs results
  in increased growth with significantly reduced
  differentiation in vitro for a period of at least
  many weeks. HSCs transduced with -catenin give
  rise to sustained reconstitution of myeloid and
  lymphoid lineages in vivo, when transplanted in
  limiting numbers. We also find that Wnt
  signalling is required for the growth response of
  normal HSCs to other cytokines, as overexpression
  of axin leads to reduced stem cell growth both in
  vitro and in vivo. Furthermore, the inhibition of
  HSC growth with frizzled-CRD and the finding that
  Wnt3a causes expansion of HSCs supports the
  interpretation that the effects of -catenin and
  axin reflect upstream Wnt activity. Finally,
  studies with HSCs containing a LEF-1/TCF reporter
  indicate that HSCs in vivo respond to endogenous
  Wnt stimulation. The expression of a number of
  Wnt proteins in the bone marrow5 and frizzled
  receptors in bone-marrow-derived progenitors and
  HSCs supports this possibility22. line of
  evidence to support the answer

92

• Most growth factors that act on HSCs in culture
  induce no or limited expansion23 or are unable to
  prevent differentiation8, 24. Context Thus, one
  of the most notable findings of our work is the
  induction of proliferation and the prevention of
  HSC differentiation by the Wnt signalling
  pathway. Unexpected finding Other signals that
  increase proliferation of HSCs include Notch20
  and sonic hedgehog25. Moreover, the
  cyclin-dependent kinase inhibitor p21Cip1/Waf1
  (ref. 26) and the transcription factor HoxB4
  (ref. 21) have been shown to be involved in
  regulating self-renewal of HSCs. Notably, Wnt
  signalling has been shown to interact with many
  of these pathways in a variety of organisms27-30,
  Context and our data show that both HoxB4 and
  Notch1 are upregulated in response to Wnt
  signalling in HSCs. This raises the possibility
  that the effects of Wnt signalling on HSCs are
  mediated through HoxB4 and/or Notch1
  Speculation . Whereas HoxB4 could act directly
  on these HSCs as demonstrated previously21,
  Notch1 action would require nearby Notch1
  ligands. possible pathways

93

• The ability of Wnt3a to induce expansion of
  HSCs is consistent with previous studies showing
  increased numbers of haematopoietic progenitors
  from mouse fetal liver and human bone marrow
  cells stimulated with Wnt-containing
  supernatants31, 32. Context/comparison with
  previous studies These studies, although
  consistent with ours, are more difficult to
  interpret as they did not use purified HSCs,
  lacked in vivo reconstitution analysis, and did
  not provide evidence of a physiological
  requirement for Wnt signalling for HSCs. Gaps in
  previous studies Components of the Wnt pathway
  have also been shown to promote proliferation of
  primitive cells in the skin33, 34, the gut35, 36
  and the brain37, and to inhibit differentiation
  to a variety of lineages in embryonic stem
  cells38, raising the possibility that Wnt
  signalling may be used as a general cue for
  self-renewal in stem and/or progenitor cells from
  diverse tissues. Context/big picture Its role
  as a self-renewal signal does not, however,
  preclude its involvement in differentiation of
  stem cells in certain contexts39.

94

• Our findings may have important implications
  for human haematopoietic cell transplantation.
  the so what? clinical implication We have
  found that soluble Wnt3a protein induces
  proliferation of highly purified human bone
  marrow HSCs in the absence of any other growth
  factor (T.R., T. Miyamoto and I.L.W., unpublished
  observation). Induction of HSC growth by Wnt
  signalling may allow in vitro expansion of a
  patient's own or an allogeneic donor's HSCs, and
  could provide an increased source of cells for
  future transplantation. clinical implication
  Finally, we have previously raised the hypothesis
  that self-renewal is a property that could be
  dangerous, as an adequate definition of cancer
  stem cells is poorly regulated self-renewal of a
  particular stage of a developmental lineage40.
  The demonstration here that the Wnt/ -catenin
  pathway may have a role in haematopoietic stem
  cell self-renewal leads us to propose that this
  pathway should be studied for a role in
  self-renewal of cancer stem cells. kickerone
  step broader, applications to cancer

95
Scientific Writing, HRP 214Discussion

• The Discussion
• The answer to the key question asked
• Whats new
• The context
• How your results fit into, contradict, or add to
  whats known or believed
• Strengths and limits of the study
• The so what? implicate, speculate, recommend
• Overall conclusion
• Powerful finish

96
Scientific Writing, HRP 214 Top 5
97
Scientific Writing, HRP 214

• 1. Peremptory v. preemptive
• Peremptory cannot be denied
• Preemptive action is one taken before an
  adversary can act
• He issued a peremptory order.
• He ordered a preemptive war in Iraq.

98
Scientific Writing, HRP 214

• 2. Subject v. patient
• A subject is a volunteer.
• A patient is under treatment by a doctor.
• The subjects in our study took a quiz about love.
• The patients in our study were being treated for
  their stomach conditions.

99
Scientific Writing, HRP 214

• 3. Strata v. stratum
• Strata is plural.
• Stratum is singular.
• We analyzed the data, adjusting for the different
  age strata.
• I was only interested in the association in the
  stratum of elderly subjects.

100
Scientific Writing, HRP 214

• 4. Averse v. adverse
• Averse means opposed and usually describes a
  persons attitude.
• Adverse means hostile, unfavorable, opposed but
  usually applies to situations, conditions, or
  eventsnot people.
• The bad weather has an adverse effect on my car.
• I would not be averse to trying that new
  restaurant.

101
Scientific Writing, HRP 214

• 5. Historic v. historical
• Historic means notable in history.
• --indicates that it in some way changed the
  course of human events
• Historical means relating to history or past
  events.
• --not necessarily historic
• The signing of the Declaration of Independence
  was a historic moment in American history.
• Professor Smith gave a historical lecture on the
  evolution of toothpicks.

102
Scientific Writing, HRP 214Homework for next
time

• Assignments for Next Week
•          Read chapter 3 of Successful Scientific
  Writing
• Write intro/background using what you learned in
  this weeks lecture.
• Email intro/background to me by class Wednesday
  August 3rd.
• Conferences next week 4th-5th (schedule posted
  email me to reserve time slot)

103
Scientific Writing, HRP 214For next week

• Next time
• Materials and Methods, Results, Figures and
  Tables