scholarly journals Analysis of Fascicular Structure and Connective Tissue Sheaths in Sural Nerve during Aging

2014 ◽  
Vol 31 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Braca Kundalić ◽  
Slađana Ugrenović ◽  
Ivan Jovanović ◽  
Natalija Stefanović ◽  
Vladimir Petrović ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Cross Sections ◽  
Sural Nerve ◽  
Statistical Significance ◽  
Volume Density ◽  
Mean Values ◽  
Age Related ◽  
Cross Section Area ◽  
Investigation Methods ◽  
Myelinated Fibres

Summary The aim of our study was to analyze the changes of connective tissue sheaths of epi-, peri- and endoneurium of sural nerve during aging. The study was conducted on sural nerve samples of 10 cases aged 9-80 years. The specimens were embedded in paraffin using standard procedures, after which 5-μm-thick cross-sections of nerve trunks were made and stained using Masson’s trichrome staining. After morphological analysis of fascicular structure and connective sheaths of the nerve, morphometric analysis was conducted using the software for digital image analysis “ImageJ”. Each investigated case was analyzed for total neural, epineurial and fascicular cross-section area, mean values of perineurial index, volume density of myelinated axons and of endoneurial content. To test the difference in mean values for statistical significance we used the Student’s T-test for small independent sample. The number of fascicles was 5-13, while the majority of the nerves had less than 10 fascicles. Fascicular structure, which included the number of fascicles and epifascicular/fascicular area ratio, did not show significant changes during aging. Perineurial thickness /fascicle size ratio statistically significantly increased in the older investigated group (p<0.05). Myelinated fibres were of smaller diameter, with more irregular form and markedly less frequent in older cases. Quantitative analysis showed statistically significant decrease in volume density of myelinated fibres in the older group. As results of applied investigation methods we found thickening of perineurial sheath of sural nerve during aging, as well as endoneurial fibrosis. Future investigations of age-related changes should focus on analysis of the components of extracellular matrix within perineurium and endoneurium.

56 COMPARISON OF THE MORPHOLOGY OF VARIOUS REGIONS OF THE CATTLE OVIDUCT IN FOUR PHASES OF THE OVARIAN CYCLE

2012 ◽  
Vol 24 (1) ◽  
pp. 140
Author(s):  
A. M. Duszewska ◽  
A. Compa ◽  
M. Zelechowska ◽  
A. Piliszek ◽  
A. Rynkowska ◽  
...  
Keyword(s):  
Cross Sections ◽  
Statistical Significance ◽  
Ovarian Cycle ◽  
Mean Values ◽  
Honestly Significant Difference ◽  
Significant Difference ◽  
Ovarian Morphology ◽  
Tukey Honestly Significant Difference ◽  
Hematoxylin And Eosin ◽  
Mucosal Folds

The oviduct provides the environment necessary for the gamete transport, completion of spermatozoa capacitation, oocyte fertilization and the early development of embryos. In cattle, all of these processes take place between Day 0 to 4 of the ovarian cycle (Day 0 is the day of ovulation). In previous studies, temporal changes in the bovine oviduct morphology were evaluated by dividing the ovarian cycle into luteal and follicular phases. In order to understand the relation between the bovine oviduct morphology and processes occurring there, the ovarian cycle has been further divided into four phases: I (Day 0–4), II (Day 5–10), III (Day 11–17) and IV (Day 18–20), with the day of ovulation considered Day 0 (1980 J. Dairy Sci. 63, 155–160). The aim of the study was to evaluate the oviduct morphology of the infundibulum, ampulla and isthmus in 4 phases of the ovarian cycle. Research material comprised cattle oviducts (classified into 1 of the 4 phases of the cycle based on ovarian morphology), dissected into infundibulum, ampulla and isthmus and subsequently sectioned and processed for histological preparations (hematoxylin and eosin, H&E, staining). Diameters of transverse cross-sections of oviduct and its lumen and thickness of tunicas: mucosa, muscularis and serosa were evaluated in relation to the region of oviduct and the phase of ovarian cycle. Values are given in μm. Statistical analysis was carried out by 1-way analysis of variance and comparisons of mean values were made with the Tukey honestly significant difference test (Statgraphics Plus 5); P < 0.05 was considered to reflect the presence of statistical significance. The comparison of the diameters of transverse cross-sections (A) of oviduct and its lumen (B) shows significant statistical differences between ampulla and isthmus within the phases: A-I (4507.26 vs 2524.47), II (4510.53 vs 2540.67), III (4503.28 vs 2534.07), IV (4500.73 vs 2533.90); B-I (4191.10 vs 1950.88), II (4173.63 vs 1986.33), III (4198.53 vs 1966.88) and IV (4192.50 vs 1959.33). There are no differences among 4 phases of the ovarian cycle. The thickness of tunicas muscularis and serosa of infundibulum (I: 26.81 vs 196.85; II: 27.03 vs 201.80; III: 26.22 vs 199.45; IV: 23.97 vs 198.01), ampulla (I: 91.51 vs 214.50; II: 90.72 vs 212.55; III: 88.61 vs 213.30; IV: 89.65 vs 206.28) and isthmus (I: 202.29 vs 216.52; II: 199.24 vs 207.74; III: 200.90 vs 212.38; IV: 200.38 vs 210.86) show only statistically significant differences within the phases, whereas the tunica mucosa shows only statistically significant differences between phases and the term of the height of epithelium at the base of mucosal folds (I: 26.49; II: 25.20; III: 24.14; IV: 29.96) and their apical parts (I: 28.09; II: 26.01; III: 25.45; IV: 30.96). In conclusion, differences in oviduct morphology are mainly region specific, whereas the epithelium morphologically infundibulum, ampulla and isthmus show variation in the 4 phases of the ovarian cycle. Supported by Grant MNiSW N311236137.

Spindle shaped bodies in foveolar cones of the baboon retina

1989 ◽  
Vol 47 ◽  
pp. 960-961
Author(s):  
W. Krebs ◽  
I. Krebs
Keyword(s):  
Cross Sections ◽  
Inclusion Bodies ◽  
Photoreceptor Cells ◽  
Papio Anubis ◽  
Retinal Photoreceptor ◽  
Age Related ◽  
Cone Cells ◽  
Membrane Bound ◽  
Oriented Parallel ◽  
Shaped Inclusion

Various inclusion bodies occur in vertebrate retinal photoreceptor cells. Most of them are membrane bound and associated with phagocytosis or they are age related residual bodies. We found an additional inclusion body in foveal cone cells of the baboon (Papio anubis) retina.The eyes of a 15 year old baboon were fixed by immersion in cacodylate buffered glutaraldehyde (2%)/formaldehyde (2%) as described in detail elsewhere . Pieces of retina from various locations, including the fovea, were embedded in epoxy resin such that radial or tangential sections could be cut.Spindle shaped inclusion bodies were found in the cytoplasm of only foveal cones. They were abundant in the inner segments, close to the external limiting membrane (Fig. 1). But they also occurred in the outer fibers, the perikarya, and the inner fibers (Henle’s fibers) of the cone cells. The bodies were between 0.5 and 2 μm long. Their central diameter was 0.2 to 0. 3 μm. They always were oriented parallel to the long axis of the cone cells. In longitudinal sections (Figs. 2,3) they seemed to have a fibrous skeleton that, in cross sections, turned out to consist of plate-like (Fig.4) and tubular profiles (Fig. 5).

scholarly journals Whole-brain 3D MR fingerprinting brain imaging: clinical validation and feasibility to patients with meningioma

2021 ◽  
Author(s):  
Thomaz R. Mostardeiro ◽  
Ananya Panda ◽  
Robert J. Witte ◽  
Norbert G. Campeau ◽  
Kiaran P. McGee ◽  
...  
Keyword(s):  
White Matter ◽  
Statistical Significance ◽  
Relaxation Times ◽  
Brain Structures ◽  
Centrum Semiovale ◽  
In Vivo Evaluation ◽  
Whole Brain ◽  
Mean Values ◽  
Caudate Head

Abstract Purpose MR fingerprinting (MRF) is a MR technique that allows assessment of tissue relaxation times. The purpose of this study is to evaluate the clinical application of this technique in patients with meningioma. Materials and methods A whole-brain 3D isotropic 1mm3 acquisition under a 3.0T field strength was used to obtain MRF T1 and T2-based relaxometry values in 4:38 s. The accuracy of values was quantified by scanning a quantitative MR relaxometry phantom. In vivo evaluation was performed by applying the sequence to 20 subjects with 25 meningiomas. Regions of interest included the meningioma, caudate head, centrum semiovale, contralateral white matter and thalamus. For both phantom and subjects, mean values of both T1 and T2 estimates were obtained. Statistical significance of differences in mean values between the meningioma and other brain structures was tested using a Friedman’s ANOVA test. Results MR fingerprinting phantom data demonstrated a linear relationship between measured and reference relaxometry estimates for both T1 (r2 = 0.99) and T2 (r2 = 0.97). MRF T1 relaxation times were longer in meningioma (mean ± SD 1429 ± 202 ms) compared to thalamus (mean ± SD 1054 ± 58 ms; p = 0.004), centrum semiovale (mean ± SD 825 ± 42 ms; p < 0.001) and contralateral white matter (mean ± SD 799 ± 40 ms; p < 0.001). MRF T2 relaxation times were longer for meningioma (mean ± SD 69 ± 27 ms) as compared to thalamus (mean ± SD 27 ± 3 ms; p < 0.001), caudate head (mean ± SD 39 ± 5 ms; p < 0.001) and contralateral white matter (mean ± SD 35 ± 4 ms; p < 0.001) Conclusions Phantom measurements indicate that the proposed 3D-MRF sequence relaxometry estimations are valid and reproducible. For in vivo, entire brain coverage was obtained in clinically feasible time and allows quantitative assessment of meningioma in clinical practice.

Anonymized Firm Data under Test: Evidence from a Replication Study

2005 ◽  
Vol 225 (5) ◽  
Author(s):  
Joachim Wagner
Keyword(s):  
Cross Sections ◽  
Statistical Significance ◽  
Original Data ◽  
Replication Study ◽  
Firm Level ◽  
Level Data ◽  
Practical Usefulness ◽  
Order Of Magnitude ◽  
Anonymized Data ◽  
Firm Data

SummaryThis paper contributes to the literature on the use of anonymized firm level data by reporting results from a replication study. To test for the practical usefulness of anonymized data I selected two of my published papers based on different cross sections of firm data. The data used there were anonymized by micro aggregation. I replicated the analyses reported in the papers with the anonymized data, and then compared the results to those produced with the original data. Frequently, the reported levels of statistical significance differ. Furthermore, statistically significant coefficients sometimes differ by order of magnitude. Therefore, at least for the moderate sample sizes used here micro-aggregated firm data should not be considered as a tool for empirical research.

scholarly journals AB0815 FIRST DEGREE RELATIVES OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS - CLINICAL, SEROLOGICAL AND IMMUNOLOGICAL CORRELATIONS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1432.2-1432
Author(s):  
B. Penev ◽  
G. Vasilev ◽  
D. Kyurkchiev ◽  
S. Monov
Keyword(s):  
Risk Factors ◽  
Systemic Lupus Erythematosus ◽  
Connective Tissue ◽  
Lupus Erythematosus ◽  
Current Knowledge ◽  
Statistical Significance ◽  
Clinical Signs ◽  
Connective Tissue Diseases ◽  
Pharmaceutical Products ◽  
Systemic Lupus

Background:Antinuclear antibodies (ANA) have been unequivocally recognized as essential for diagnosis and play both pathogenic and diagnostic roles in systemic lupus erythematosus (SLE). SLE and ANA have also been found to be more often among relatives of SLE patients. ANA and other immunological changes are known to appear prior to the clinical onset of the disease and thus can be used as predictors. Studies have reported that relatives of SLE patients who later transitioned to SLE displayed more lupus-associated autoantibody specificities and had early clinical signs. They also displayed elevated baseline plasma levels of inflammatory mediators, including B-lymphocyte stimulator (BLyS) and interferon-associated chemokines, with concurrent decreases in levels of regulatory mediators, e.g. tumor growth factor (TGF)-β. Commonly recognized risk factors for SLE are signs of past Epstein-Barr (EBV) infection, use of estrogen drugs and current smoking. It seems that ANA, immunologic changes and risk factors have not been investigated together in relatives of SLE patients.Objectives:The aim of the study was to determine the relative prevalence of clinical signs of SLE or connective tissue disease (CTD), smoking, use of estrogen drugs and levels of circulating ANA, BLyS, IFN-α, TGF-β, anti-EBV viral capsid antigen (VCA) IgM and IgG antibodies among sera of FDR, non-FDR healthy individuals and SLE patients.Methods:Forty three FDRs of SLE patients were studied along with 15 SLE patients and 15 clinically healthy subjects as control groups. The FDRs and the healthy answered a questionnaire about early clinical signs of CTD, smoking and estrogen use history. The questionnaire was developed based on the existing Screening Questionnaire for Connective Tissue Diseases and current knowledge of most early signs of CTD. Blood samples were obtained and tested for ANA, both by indirect immunofluorescence and immunoblot, anti-dsDNA by ELISA. ELISA was also performed to measure levels of BLys, IFN-α, TGF-β, anti-EBV IgM and IgG.Results:More than half of the FDRs displayed ANA in titer 1:160 or more, with predominately AC-4 type of fluorescence according to International Classification on ANA Patterns (ICAP) compared to only AC-1 and AC-0 among patients and controls respectively. A correlation between the ANA titer and the number of complaints was found. This was particularly valid or reported skin complaints and oral ulcers which appeared more frequently when ANA was 1:320 or above (p=0,018 and 0,038 respectively). Furthermore, oral ulcerations showed positive correlation with the presence of anti-Ro60. No associations were found in the healthy group between reported complaints and ANA titers. Smoking and estrogen use did not differ across the three groups. Patients showed significant differences in levels of BLys (p=0,027), TGF-β (p=0,019) and anti-EBV IgG (p=0.041) compared to both FDRs and controls. Without reaching statistical significance, levels of TGF-β tend to split the FDR group into “healthy-like” and “SLE-like”.Conclusion:Our results show that FDR ANA levels are between those of SLE patients and healthy subject groups. This is consistent with previous studies. The data also suggest that ANA positivity correlates with reported complaints, some of which could be interpreted as very early clinical signs of SLE. Of note, anti-Ro60 is known to be among the earliest ANA that appear in “future” SLE patients and in this study they are related to oral complaints that could be caused by early sicca phenomena. Immunologically, our data support previous findings [1] that the FDRs are a heterogenic group with different “lupus-developing” potential.References:[1]Munroe МE. et al, Soluble Mediators and Clinical Features Discern Risk of Transitioning to Classified Disease in Relatives of Systemic Lupus Erythematosus Patients, Arthritis Rheumatol. 2017 March; 69(3): 630–642.Disclosure of Interests:Bogdan Penev: None declared, Georgi Vasilev: None declared, Dobroslav Kyurkchiev: None declared, Simeon Monov Speakers bureau: I have been paid for giving lectures on statistical data on efficacy of many pharmaceutical products on various companies

Alteration in the Proportion of CD4 T Lymphocytes in a Subgroup of Human Immunodeficiency Virus-Exposed-Uninfected Children

PEDIATRICS ◽  
1994 ◽  
Vol 93 (4) ◽  
pp. 624-630
Author(s):  
Matthew Gesner ◽  
Vana Papaevangelou ◽  
Song-He Chen ◽  
Tiina Moore ◽  
Keith Krasinski ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Statistical Significance ◽  
Weighted Average ◽  
Rate Of Change ◽  
Entire Study ◽  
Age Related ◽  
Wilcoxon Rank Sum Test ◽  
Immunodeficiency Virus ◽  
Cd4 Lymphocyte ◽  
Cd4 Percentage

Objective. The age-related changes in the proportion of CD4 and CD8 lymphocytes in human immunodeficiency virus (HIV)-seronegative children born to HIV-infected mothers (seroreverters) were compared with the changes in these lymphocyte subsets in children born to seronegative women to assess a possible effect of exposure to HIV without infection. Design. There were 146 seroreverter and 72 seronegative children. The median CD4 and CD8 percentages for each of these two groups of children were compared retrospectively at 3-month intervals from birth through 27 months and at a tenth interval for the time beyond 27 months. The weighted average of the within-subject rate of change of CD4 and CD8 percentages were also compared between the two groups. Finally, for each subject, the proportion of the subject's CD4 percentage assays which were &lt;10th percentile of the entire study population (30%) was calculated, and the distributions of the subject-specific proportions were then compared between the seronegative and seroreverter groups using the Wilcoxon rank sum test. The proportion of CD8 assays &lt;10th percentile (12%) or &gt;90th percentile (26%) were also computed for each subject, and the distributions of the proportions were compared similarily. Results. The median CD4 percentage for seroreverter children was lower than that for the seronegative children at every interval from birth through 27 months and for the last interval for values obtained at greater than 27 months, although the comparison was statistically significant only at the 4- to 6-month period. The weighted average of the within-subject rate of change of CD4 percentage was -0.09 and -3.0 per year (P .04), and of CD8 percentage was 1.3 and 1.0 (P = .67), for the seroreverter and seronegative children, respectively. There were significantly more children in the seroreverter group than in the seronegative group who had repeated assays in which the CD4 percentage was &lt;10th percentile for age (P &lt;.00005). In addition, there was a subset of 10 seroreverter children (6.8%) who had CD4 percentages &lt;30% on &gt;50% of their assays, as compared with only one (1.4%) seronegative child. The proportion of CD8 assays &lt;10th percentile or &gt;90th percentile were not significantly different between the two groups of children. Conclusions. The CD4 proportions were persistently lower in the seroreverter than in the seronegative population, although only reaching statistical significance in 1 of 10 3-month intervals. This finding may be due to a subgroup of seroreverter children who have persistently low CD4 lymphocyte percentages.

Application of 25-National Eye Institute Visual Function Questionnaire in ophthalmological patients

2020 ◽  
Vol 2 (3) ◽  
pp. 1-8
Author(s):  
Luciano Mesquite Simmo ◽  
Carissa Fouad Ibrahim ◽  
Senice Alvarenga Rodrigues Silva ◽  
Thai Nunes Andrade ◽  
Doora Faleiros Leite ◽  
...  
Keyword(s):  
Visual Function ◽  
Peripheral Vision ◽  
Statistical Significance ◽  
Eye Diseases ◽  
Age Related Macular Degeneration ◽  
Control Group ◽  
Ischemic Optic Neuropathy ◽  
Age Related ◽  
Visual Function Questionnaire ◽  
The Impact

Objective: To compare the vision-targeted health related quality of life (HRQOL) between neuro-ophthalmological patients and other eye diseases by the National Eye Institute 25-Item Visual Function Questionnaire. Methods: Cross sectional study with a control group and patients with the following pathologies: primary open-angle glaucoma (POAG), diabetic retinopathy (DR), age-related macular degeneration (ARMD), non-arteritic ischemic optic neuropathy (NAION), intracranial hypertension (IH), optic neuritis (ON), ptosis and cataract. Results: All comparisons of the subscales scores among the control group and the patient groups were statistically significant (p<0.05) except for “ocular pain” (p=0.160), “social functioning” (p=0.052) and “peripheral vision” (p=0.112). The control group had the best scores across all dimensions of the NEI VFQ-25. Interestingly, the ARMD and cataract groups presented the best and worst total scores of NEI VFQ-25, respectively. The lowest subscales scores were found in the cataract, in the NAION/ON, and in the POAG groups. Finally, the comparison between the NAION/ON/IH patients and the other eye diseases did not show statistical significance in any subscale. Conclusion: The NEI VFQ-25 showed the impact of various eye conditions in vision-targeted HRQOL, and no difference was measured between neuro-ophthalmological patients and other eye diseases

scholarly journals Therapeutic efficacy of connective tissue autotransplants with periosteum and platelet rich plasma in the management of gingival recession

2013 ◽  
Vol 70 (7) ◽  
pp. 664-669 ◽  
Author(s):  
Bojan Jovicic ◽  
Zoran Lazic ◽  
Milica Nedic ◽  
Stevo Matijevic ◽  
Aleksandra Gostovic-Spadijer
Keyword(s):  
Connective Tissue ◽  
Surgical Procedures ◽  
Platelet Rich Plasma ◽  
Statistical Significance ◽  
Surgical Techniques ◽  
Gingival Recession ◽  
Contralateral Side ◽  
Test Results ◽  
Keratinized Tissue ◽  
Student’S T

Background/Aim. Gingival recession progression in clinical practaice has influenced the development of various surgical procedures and techniques for solving esthetic imperfections and subjective difficulties coused by gingival recession. The aim of this study was to verify efficacy of surgical procedures and to compare both of surgical procedures through the keratinized tissue width. Methods. The study included 20 teeth with gingival recesion, M?ller class I and II. Ten teeth with gingival recession were treated with connective tissue autotransplants with periosteum in combination with coronary guided surgical flap (CTG group). On the contralateral side 10 teeth with gingival recession were treated with the same surgical procedures but in combination with platelet-rich plasma (CTGPRP group). We measured the keratinized tissue width. For statistical significance we used the Student's t-test. Results. The study reveled a statistical significance in reducing vertical deepress of recession by both used treatments. Root deepness in CTG and CTG-PRP group was 90% and 93.5%, respectively. With both surgical techniques we achieved larger zone of keratinized gingiva but with a wide zone of keratinized tissue in CTG - the PRP group. Conclusion. The concept regeneration technique with PRP and with the stimulating influence of platele activated growth factors results in the regeneration of deep periodontal tissue as an important prerequisite for the successful treatment of gingival recession.

scholarly journals THE IMPORTANCE OF EDUCATION TO REDUCE SELF-DESTRUCTIVE NAIL HABITS

2021 ◽  
Vol 4 ◽  
pp. 491-499
Author(s):  
Ilze Upeniece ◽  
Monta Beltiņa
Keyword(s):  
Clinical Practice ◽  
General Education ◽  
Statistical Significance ◽  
Target Population ◽  
Control Group ◽  
Age Related ◽  
Nail Changes ◽  
Group 2 ◽  
And Control ◽  
Traumatic Damage

Onychophagia and onychotillomania are rarely seen in clinical practice and are considered undervalued. The study aims were to determine the prevalence of onychophagia and onychotillomania habit in the patient group with hand nail damage and control group, to determine which would be the target population to educate. Patients were interviewed about self-destructive habits. Excel and SPSS were used for data analysis. In the nail damage group, 28.6% of the respondents showed self-destructive habits and past habits – 31.4%. In the control group, the result was 22.9% and 31.4%. For 74.3% of patients the cause of nail damage was skin disease (including 61.54% of respondents with nail damage who have psoriasis), for 5.7% it was age-related nail changes, for 20% traumatic damage and for 57.14% of them it was a result of self-destructive habit. In the nail damage group both – present and past self-destructive habits are higher than in the control group, but it has no statistical significance (p=0.785). 1)The prevalence of onychophagia and onychotillomania does not differ between patients and control group. 2)General education of the population is necessary to actualize this problem, which can worsen nail changes.

scholarly journals Impact of satellite viewing swath width on global and regional aerosol optical thickness statistics and trends

2013 ◽  
Vol 6 (6) ◽  
pp. 10117-10163 ◽  
Author(s):  
P. R. Colarco ◽  
R. A. Kahn ◽  
L. A. Remer ◽  
R. C. Levy
Keyword(s):  
Optical Thickness ◽  
Statistical Significance ◽  
Sampling Strategy ◽  
Aerosol Optical Thickness ◽  
Mean Values ◽  
Sampling Artifacts ◽  
Aerosol Loading ◽  
Decadal Scale ◽  
Along Track ◽  
The Impact

Abstract. We use the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite aerosol optical thickness (AOT) product to assess the impact of reduced swath width on global and regional AOT statistics and trends. Ten different sampling strategies are employed, in which the full MODIS dataset is sub-sampled with various narrow-swath (~400–800 km) and curtain-like (~10 km) along-track configurations. Although view-angle artifacts in the MODIS AOT retrieval confound direct comparisons between averages derived from different sub-samples, careful analysis shows that with many portions of the Earth essentially unobserved, the AOT statistics of these sub-samples exhibit significant regional and seasonal biases. These AOT spatial sampling artifacts comprise up to 60% of the full-swath AOT value under moderate aerosol loading, and can be as large as 0.1 in some regions under high aerosol loading. Compared to full-swath observations, narrower swaths exhibit a reduced ability to detect AOT trends with statistical significance, and for curtain-like sampling we do not find any statistically significant decadal-scale trends at all. An across-track sampling strategy obviates the MODIS view angle artifact, and its mean AOT converges to the full-swath mean values for sufficiently coarse spatial and temporal aggregation. Nevertheless, across-track sampling has significant seasonal-regional sampling artifacts, leading to biases comparable to the curtain-like along-track sampling, lacks sufficient coverage to assign statistical significance to aerosol trends, and is not achievable with an actual narrow-swath or curtain-like instrument. These results suggest that future aerosol satellite missions having significantly less than full-swath viewing are unlikely to sample the true AOT distribution well enough to determine decadal-scale trends or to obtain the statistics needed to reduce uncertainty in aerosol direct forcing of climate.

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