Identical Sections Of Sentences Biology Essay

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Correlation analyses were performed with Spearman rank order correlation. The Wilcoxon rank sum test was used to test for differences in haematological outcomes between exposed subjects and controls. Subsequent analyses were performed on the 3 groups of study subjects: controls; subjects exposed to ≤ 31 ppm benzene; and subjects exposed to > 31 ppm benzene. Continuous outcome data that were not normally distributed were logarithmically transformed. Analysis of covariance was used to test for group differences in continuous outcomes. Unconditional logistic regression was used to test for differences in the proportion of subjects with a blood morphology abnormality among exposed workers vs controls and to evaluate potential confounders.

Person-years at risk were accumulated from 6 months after study entry (1 January 1972) or date of hire, if later, to the earliest of the following events : date of diagnosis of cancer, death, employment in a job of unknown exposure (<1% of person-years), date of loss to follow-up (<1% of subjects) or end of follow-up (Dec 31, 1987).Subjects were categorised by occupations in coatings applications (mostly painters), chemicals production, shoe production, and other or mixed occupations.Ratios of incidence rates for haematological neoplasms in the exposed group were compared with rates in the unexposed group and relative risks were determined using Poisson regression analysis with stratification by age and sex. Tests for linear trend (two-sided) of increasing risk with increasing extent of benzene exposure were carried out, on the basis of the mean of years in duration-exposure categories, the log of the mean of parts per million in average-exposure categories, and the log of the mean of parts per million-years in cumulative exposure categories.

3. Hayes et al (1997)

Table 1 from Robust summary (similar to Table 2 of paper but doesn't have rows for other leukaemia).

Table 1. Relative risk (RR)* for hematologic neoplasms and related conditions according to extent of exposure to benzene

Benzene-exposed group

Unexposed referent group

Haematological condition

Average, ppm$

Constant, ppm§

Duration, yrs

Cumulative, ppm-yrs

<10

10-24

>25

P for trend

<10

10-24

>25

P for trend

<5

5-9

>10

P for trend

<40

40-99

>100

P for trend

All Haem neoplasms

Cases

24

16

18

21

8

11

16

17

25

18

11

29

13

RR

2.2

3.1

2.8

.003

2.1

3.2

2.9

0.002

3.1

3.3

2.0

.24

2.2

2.9

2.7

.004

95% CI

1.1-4.2

1.5-6.5

1.4-5.7

1.0-4.1

1.3-7.6

1.3-6.6

1.5-6.6

1.6-6.8

1.0-3.9

1.1-4.5

1.3-6.5

1.4-5.2

NHL

Cases

7

2

7

7

0

3

1

4

11

6

1

9

3

RR

2.7

1.7

4.7

.04

3.0

-

3.5

.15

0.7

3.3

4.2

.01

3.3

1.1

3.5

.02

95% CI

0.7-10.6

0.3-10.2

1.2-18.1

0.8-11.6

-

0.7-17.3

0.1-7.2

0.7-14.7

1.1-15.9

0.8-13.1

0.1-11.1

0.9-13.2

Leukemia

Cases

15

13

10

12

7

7

14

11

13

11

8

19

9

RR

2.0

3.7

2.3

.02

1.7

4.0

2.8

.009

4.0

3.1

1.5

.98

1.9

3.1

2.7

.04

95% CI

0.9-4.5

1.6-8.7

0.9-5.7

0.7-4.1

1.5-10.7

1.0-7.4

1.7-9.6

1.3-7.5

0.6-3.6

0.8-4.7

1.2-8.0

1.2-6.0

ANLL

Cases

7

9

5

6

4

5

9

6

6

5

5

11

4

RR

2.0

5.8

2.6

.04

1.9

4.9

4.4

.008

5.6

3.6

1.6

.81

1.9

4.3

3.6

.06

95% CI

.06-7.0

1.8-18.9

0.7-9.9

0.5-6.8

1.2-19.8

1.2-16.4

1.7-18.7

1.0-12.9

0.4-5.7

0.5-7.0

1.1-16.0

1.1-11.6

ANLL/MDS

Cases

11

9

8

10

4

8

10

7

11

7

7

14

4

RR

3.2

5.8

4.1

.01

3.2

5.1

7.1

.0003

6.6

4.3

2.8

.48

2.7

6.0

4.4

.01

95% CI

1.0-10.1

1.8-18.8

1.2-13.2

1.0-10.3

1.3-20.6

2.1-23-7

2.0-21.6

1.3-14.8

0.9-9.1

0.8-9.5

1.8-20.6

1.4-13.5

Person -y,x103

352

157

188

324

88

121

249

170

278

300

119

279

*Referent: RR =1.0 for unexposed workers, with all risks adjusted for age and sex.

NHL = non-Hodgkin's lymphoma; ANLL = acute non-lymphocytic leukaemia; MDS = myelodysplastic syndromes; other leukaemia; includes leukaemias other than ANLL and leukaemias not otherwise specified

ppm = part(s) per million

§This category encompasses a group of person-years for workers who were always exposed at the indicated levels

P values are two-sided

Groups for trend test: unexposed and exposure of <10, 10-39, 40-99, 100-399, and >400 ppm-years

95% CI = confidence interval.

4. Hayes et al (1997)

Table 2 from Robust Summary (almost identical to Table 3 of paper)

Table 2. Relative risk for selected haematological conditions among benzene-exposed workers according to recency of exposure

NHL

ANLL/MDS

# Recent exposure, ppm-yrs

Recent exposure, ppm-yrs

Distant exposure,

ppm-yrs§

None

<40

>40

Total

None

<40

>40

Total

None

Cases

3

0

3

5

9

14

P-Y (x103)

*Referent

218

136

354

Referent

218

136

354

RR

2.5

1.5

3.7

9.1

6.0

95% CI

0.5-13.2

0.3-7.6

1.0-13.9

2.8-29.7

1.9-18.4

<40

Cases

0

3

1

4

0

3

4

7

P-Y (x103)

3

97

46

147

3

97

46

147

RR

-

3.4

2.6

3.1

-

2.4

7.4

3.8

95% CI

0.7-17.4

0.3-25.3

0.7-14.3

0.5-10.7

1.8-29.7

1.1-13.0

>40

Cases

0

2

7

9

0

1

6

7

P-Y (x103)

6

32

159

197

6

32

159

197

RR

-

6.4

4.7

4.9

-

2.0

2.7

2.5

95% C1'

1.0-41.1

1.2-18.9

1.3-18.9

0.2-18.5

0.8-9.8

0.7-8.7

Total

Cases

0

8

8

0

9

19

P-Y (x103)

9

347

342

9

347

342

RR

3.4

2.9

2.9

5.3

95% CI

0.9-13.0

0.8-10.8

0.9-9.3

1.8-15.6

Linear trend tests: (never exposed [referent), >0 to <10, 10-39, 40-99, 100-399, and '400 ppm-yrs, in time period).

NHL                                            ANLL/MDS

Recent exposure, P = .15.                 Recent exposure, P = .003

Distant exposure, P = .005.                 Distant exposure, P = .51

*Referent: RR = 1.0 for unexposed workers, with all risks adjusted for age and sex.

NHL = non-Hodgkin's lymphoma; ANLL = acute non-lymphocytic leukaemia; MDS = myelodysplastic syndromes.

#Recent exposure: cumulative benzene exposure (parts per million [ppm]-years, lag 1.5 years) in period <10 years prior to diagnosis

§Distant exposure: cumulative benzene exposure (ppm-years, lag 1.5 years) in --10 years prior to diagnosis.

P-Y (x103) = person years per 1000

CI = confidence interval.

RR = relative risk

5. Rushton and Romaniuk (1997)

Robust summary - Details of exposure

Work histories were collected for the cases and controls, together with information about the terminals at which they had worked, fuel compositions, and occupational hygiene measurements of benzene. These data were used to derive quantitative estimates of personal exposure to benzene.

A representative set of benzene measurements (referred to as base estimates), which were also well characterised - that is, had values for factors considered to affect exposure - was assembled for different tasks in the distribution centres. The base estimate exposure measurements (ppm) were time weighted to eight hours (8-hour TWA). These base estimates were then adjusted to take account of changes in factors which were considered to affect exposure to give a workplace estimate. The six adjustment factors used were job activity (to adjust for known differences in tasks from those covered in the base estimate), number of loads handled per day, loading technology (in particular to adjust for differences between top splash and top submerged loading), percentage of benzene in the fuel, product mix (to adjust for handling products other than gasolines-such as diesel-during the same work), and air temperature.

Exposures were further classified qualitatively into 12 categories according to whether they were likely to have occurred in intermittent peaks, defined by frequency (daily, weekly, or monthly), intensity (1-3 ppm, > 3 ppm), and duration (1-15 minutes, 15-60 minutes). The potential for skin exposure to benzene was estimated, for each job in the work history, as none, low, medium, or high. As well as cumulative exposure (ppm-years; both categorised into discrete ranges and as a continuous variable), mean intensity (mean 8-hour TWA, (ppm); cumulative exposure divided by duration of employment), maxi-mum intensity (maximum 8-hour TWA, (ppm); highest intensity for any job in the work history), and years of employment have been analysed. Cumulative exposure was analysed in (a) quintiles, primarily to check assumptions of linearity, and (b) in four categories which rep-resented a working lifetime of 45 years (< 0.45, 0.45-4.49, 4.5-44.99, > 45 ppm-years) although only 5 subjects (1%) were exposed to > 45 ppm-years. To aid comparison of results between different sub-groups the cumulative exposure quintiles for all leukaemias (< 0.26, 0-26-0-59, 0.60-1.64, 1.65-4.78, ≥ 4-79 ppm-years) were used for all analyses, assuming the most probable exposure to white oil or black oil when this uncertainty arose. The categorisations for maximum and mean intensities of exposure and duration of employment were chosen by examining the distribution of these variables for the whole study sample before separating them into cases and controls.

6. Vermeulen et al (2004)

Table is clearly lifted from Table 3 of paper but doesn't have all the columns of the original

Table 1:Exposure to benzene and toluene per factory summarized for different production processes and direct handling of glues

 

 

Gluea

K (%)b 

N

Benzene (ppm)Arithmetic mean

Toluene (ppm)Arithmetic mean

Factory A

 

37 (68%)

116

21.86

9.52

1 Cutting

 

14 (100%)

41

10.96

5.35

2 Modelling

B

6 (27%)

18

9.04

4.42

3 Fitting

A

14 (100%)

47

29.31

12.54

4 Finishing

A

3 (75%)

10

54.64

21.61

Factory B

 

213 (38%)

2667

3.46

15.88

1 Cutting

 

30 (60%)

427

0.45

1.49

2 Modelling

 

59 (32%)

735

2.74

6.37

  2a Gluing

C, E

9 (20%)

114

5.35

10.67

  2b Other

 

50 (36%)

621

2.26

5.58

3 Fitting

 

90 (38%)

1096

2.19

26.29

  Heel/inner sole

 

 

 

 

 

  3a Gluing

C,D,E

15 (43%)

186

3.61

29.30

  3b Other

 

35 (34%)

434

1.70

15.49

  Outer sole

 

 

 

 

 

  3c Gluing

D, G, H, I

13c(50%)

147

1.53

58.83

  3d Other

 

29c(41%)

329

2.33

24.30

4 Finishing

 

20 (30%)

241

8.35

18.96

5 Packing

 

14 (58%)

168

15.55

21.81

  5a Gluing

F

6 (75%)

72

24.18

23.02

  5b Packing

 

8 (50%)

96

9.08

20.91 K = number of workers; N = number of measurements

a: A: Treatment glue, B: Gasoline glue, C: latex glue, D: Resin glue, E: Gasoline glue, F: Benzene glue, G: Treatment glue 1, H: Treatment glue 2, I: Treatment glue 3.

bPercentage of workforce

cOne worker changed job within this section and therefore the total number of workers in the sub-categories does not equal the total number of workers in the production functi

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