255 research outputs found
Extreme southern locations for moss sporophytes in Antarctica
Abundant immature sporophytes of the moss Pottia heimii are reported from the Lower Taylor Valley, McMurdo Dry Valleys and from Cape Chocolate, Victoria Land. These finds extend the reported southern limit for the occurrence of abundant moss sporophytes to 77° 55′S
Technical application and the level of discomfort associated with an intramuscular electromyographic investigation into gluteus minimus and gluteus medius
Our current theoretical understanding of gluteus minimus (GMin) and gluteus medius (GMed) function is primarily based on cadaveric studies and biomechanical modelling. There is an absence of electromyographic (EMG) research that aims to verify this understanding, particularly in relation to the potentially unique functional roles of structurally distinct segments within GMin (anterior and posterior) and GMed (anterior, middle and posterior). The aim of this paper is to provide a comprehensive technical description for inserting intramuscular EMG electrodes into uniquely oriented segments of GMin and GMed; and to report the levels of discomfort associated with gluteal intramuscular electrode insertions. Fifteen healthy volunteers took part in a series of walking trials after intramuscular EMG electrodes were inserted into segments of GMin (×2) and GMed (×3) according to previously verified guidelines. Visual analogue scores following walking trials at comfortable and fast speed indicate that discomfort levels associated with these insertions were low (2.4. ±. 1.4 and 1.6. ±. 0.7 respectively). The technical descriptions and illustrations provided in this paper will allow trained intramuscular electromyographers to insert electrodes into these muscle segments with confidence
Gluteus medius: an intramuscular EMG investigation of anterior, middle and posterior segments during gait
Previous electromyographic (EMG) studies of gluteus medius (GMed) have not accurately quantified the function of the three proposed structurally and functionally unique segments (anterior, middle and posterior). Therefore this study used anatomically verified locations for intramuscular electrode recordings in three segments of GMed to determine whether the segments are functionally independent. Bipolar fine wire electrodes were inserted into each segment of GMed in 15 healthy individuals. Participants completed a series of four walking trials, followed by maximum voluntary isometric contractions (MVICs) in five different positions. Temporal and amplitude variables for each segment were compared across the gait cycle using ANOVA. The relative contributions of each segment to the MVIC trials were compared with non-parametric tests. All segments showed a biphasic response during the stance phase of gait. There were no differences in amplitude variables (% MVIC) between segments, but the anterior segment had a later peak during both the first and second bursts. For the MVIC trials, there were significant differences in amplitude between segments in four of the five test positions. These data indicate that GMed is composed of three functionally independent segments. This study contributes to the theoretical understanding of the role of GMed
Gluteus minimus: an intramuscular EMG investigation of anterior and posterior segments during gait
Gluteus minimus is believed to consist of two structurally and functionally unique segments (anterior and posterior); however there is a lack of electromyography (EMG) research that attempts to verify current theoretical knowledge of this muscle. The purpose of this study was therefore to evaluate the function of gluteus minimus during gait, and to determine whether anterior and posterior segments are functionally independent. Bipolar fine wire intramuscular EMG electrodes were inserted into anterior and posterior gluteus minimus segments of fifteen healthy volunteers (9 males) according to previously verified guidelines. Participants completed a series of four walking trials, followed by maximum voluntary isometric contractions in five different positions. Temporal and amplitude variables for each segment were compared across the gait cycle with independent t-tests. The relative contribution of each segment to the maximum resisted trials was compared with Mann-Whitney U tests (α=0.05). Anterior and posterior segments were contracting at different relative intensities for three of the five maximum resisted trials (effect size=0.39 to 0.62,
Optical coherence tomography in the assessment of acute changes in cutaneous vascular diameter induced by heat stress.
There are limited imaging technologies available that can accurately assess or provide surrogate markers of the in vivo cutaneous microvessel network in humans. In this study, we establish the use of optical coherence tomography (OCT) as a novel imaging technique to assess acute changes in cutaneous microvessel area density and diameter in humans. OCT speckle decorrelation images of the skin on the ventral side of the forearm up to a depth of 500 μm were obtained prior to and following 20-25 mins of lower limb heating in eight healthy males (30.3±7.6 yrs). Skin red blood cell flux was also collected using laser Doppler flowmetry probes immediately adjacent to the OCT skin sites, along with skin temperature. OCT speckle decorrelation images were obtained at both baseline and heating time points. Forearm skin flux increased significantly (0.20±0.15 to 1.75±0.38 CVC, P<0.01), along with forearm skin temperature (32.0±1.2 to 34.3±1.0°C, P<0.01). Quantitative differences in the automated calculation of vascular area densities (26±9 to 49±19%, P<0.01) and individual microvessel diameters (68±17 to 105±25 μm, P<0.01) were evident following the heating session. This is the first in vivo within-subject assessment of acute changes in the cutaneous microvasculature in response to heating in humans and highlights the use of OCT as an exciting new imaging approach for skin physiology and clinical research
The Genomic Signature of Crop-Wild Introgression in Maize
The evolutionary significance of hybridization and subsequent introgression
has long been appreciated, but evaluation of the genome-wide effects of these
phenomena has only recently become possible. Crop-wild study systems represent
ideal opportunities to examine evolution through hybridization. For example,
maize and the conspecific wild teosinte Zea mays ssp. mexicana, (hereafter,
mexicana) are known to hybridize in the fields of highland Mexico. Despite
widespread evidence of gene flow, maize and mexicana maintain distinct
morphologies and have done so in sympatry for thousands of years. Neither the
genomic extent nor the evolutionary importance of introgression between these
taxa is understood. In this study we assessed patterns of genome-wide
introgression based on 39,029 single nucleotide polymorphisms genotyped in 189
individuals from nine sympatric maize-mexicana populations and reference
allopatric populations. While portions of the maize and mexicana genomes were
particularly resistant to introgression (notably near known
cross-incompatibility and domestication loci), we detected widespread evidence
for introgression in both directions of gene flow. Through further
characterization of these regions and preliminary growth chamber experiments,
we found evidence suggestive of the incorporation of adaptive mexicana alleles
into maize during its expansion to the highlands of central Mexico. In
contrast, very little evidence was found for adaptive introgression from maize
to mexicana. The methods we have applied here can be replicated widely, and
such analyses have the potential to greatly informing our understanding of
evolution through introgressive hybridization. Crop species, due to their
exceptional genomic resources and frequent histories of spread into sympatry
with relatives, should be particularly influential in these studies
1993 Progress Reports
The 1993 Progress Reports which contain Blueberry Tax Supported Weed Management and Pruning Project Reports, and CSRS Supported Weed Management and Pruning Project Reports, pertain to and report on research conducted in 1992. They were prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include:
Progress Reports
1. Effects of Irrigation on Low bush Blueberry Yield and Quality
2. Economics of Investing in Irrigation for Lowbush Blueberries
3. Diammonium Phosphate Study
4. Phosphorus Dose/Response Curve
5. Winter Injury Protection by Potassium
6. Multiple Cropping of Wild Stands
7. Effect of Boron on Lowbush Blueberry Fruit Set and Yield
8.Determination of Pesticide Residue Levels in Freshly Harvested and Processed Lowbush Blueberries
9. Effects of Calcium Salts and Citric Acids on the Quality of Canned Lowbush Blueberries- missing
10. Investigation of PreProcess Changes- missing
11. The Effect of Fertilization and Irrigation on Blueberry Fruit Control - missing
12. Pollination Ecology of Lowbush Blueberry in Maine
13. Control of Secondary Blueberry Pests
14. Control of Blueberry Maggot
15. Biology and Action Thresholds of Secondary Blueberry Pests
16. Cold-Hardiness of Native Lowbush Blueberries
17. Design, Fabrication, and Testing of an Experimental Sterilizer for Blueberry Fields
18. Canned Product Quality - Heat Resistant Molds
19. Sanitation for Disease Control
Blueberry Tax Supported Weed Management and Pruning Project Reports
20. Evaluation of Postemergence Applications of Tribenuron Methyl for Bunchberry Control
21. Comparison of Poast and Select for Suppression of Bunchgrass
22. Effect of Time of Fall Pruning on Growth and Productivity of Blueberries. and Evaluation of Infrared Burner to Prune Blueberries
23. Evaluation of Velpar impregnated DAP for weed control
24. Thresholds of Dogbane and Bracken Fern for Mechanical and Chemical Control in Lowbush Blueberry Fields
25. Effect of Time and Rate of Application of Clopyralid for Control of Vetch in Lowbush Blueberries
26. Hexazinone Ground Water Survey
27. Composting Blueberry Processing Waste
28. Hexazinone Movement in a Blueberry Soil in Maine
CSRS Supported Weed Management and Pruning Project Reports
29. Evaluation of the Suitability of Remote Sensing to Evaluate Plant Cover in Lowbush Blueberry Fields
30. Obstruction Removal in Lowbush Blueberry Fields
31. Evaluation of Pressurized Rope Wick Wick Master Wiper for Treating Weeds Growing Above Lowbush Blueberries
32. Evaluation of Infrared Burner for Weed Control
33. Blueberry Extension Education Program Base
Miscellaneous
34. Comparison of N, NP, and NPK Fertilizers to Correct Nitrogen and Phosphorus Deficienc
1992 Blueberry Research Progress Reports
The 1992 Blueberry Research Progress Reports pertain to and report on research conducted in 1991, and were prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include:
1992 CSRS Progress Reports:
1. Investigation of Groundwater Resources
2. Sprinkler Irrigation
3. Investigation of Preprocess Changes Leading to Berry Spoilage
4. Effect of Fertilization and Irrigation on Blueberry Quality
5. Effects of Calcium Salts and Citric Acid on Quality of Canned Lowbush Blueberries
6. Pollination of Lowbush Blueberry by Native Bees
7. Application of Heat for Controlling Insects
8. Investigations of Lowbush Blueberry Fruit Bud Cold-Hardiness
9. Steam Sterilization in Lowbush Blueberry Fields
10. Heat-Tolerant Molds
11. Vacuum Sanitation for Disease Control
12. Evaluation of Infrared Burner for Weed Control
13. Evaluation and Modification of Commercial Herbicide Wipers
14. Evaluation of Remote Sensing to Estimate Plant Cover in Lowbush Blueberry Fields
15. Comparison of Three Mechanical Blueberry Harvesters vs. Hand Raking
Advisory Committee Research Reports:
16. Biology and action thresholds of secondary blueberry insects
17. Control of secondary blueberry pests
18. Control of blueberry maggot
19. Effects of calcium salts and citric acid on the quality of canned lowbush blueberries
20. The effects of postharvest handling on the dietary fiber and ellagic acid content of lowbush blueberries
21. Investigation of preprocessing changes that could lead to development of simple and inexpensive method to measure preprocessing berry spoilage
22. Determination of pesticide residue levels in fresh and processed lowbush blueberries
23. Vacuum sanitation for disease control
24. Heat-tolerant molds
25. Seedling pruning study
26. Effect of time and rate of application of Clopyralid for control of Vetch in lowbush blueberries
27. Evaluation and modification of commercial herbicide wipers
28. Effect of time of application and formulation of Hexazinone (Velpar) on Blueberry and Bunchberry
29. Evaluation of postemergence applications of Tribenuron Methyl for Bunchberry control
30. Thresholds of Dogbane and Bracken Fern by mechanical and chemical control in lowbush blueberry fields
31. Evaluation of the suitability of remote sensing to evaluate plant cover in lowbush blueberry fields
32. Evalution of infrared burner for weed control
33. Effect of time of fall pruning on growth and productivity of blueberry and evaluation of infrared burner to prune blueberries
34. Effect of Boron on lowbush blueberry fruit set and yield
35. Winter injury protection by potassium
36. Multiple cropping of wild stands
37. Nitrogen-Phosphorus study
38. Phosphorus dose/response curve
39. Investigations of lowbush blueberry fruit bud cold-hardines
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Reply to: New Meta- and Mega-analyses of Magnetic Resonance Imaging Findings in Schizophrenia: Do They Really Increase Our Knowledge About the Nature of the Disease Process?
This work was supported by National Institute of Biomedical Imaging and Bioengineering Grant No. U54EB020403 (to the ENIGMA consortium)
Connectome architecture shapes large-scale cortical alterations in schizophrenia: a worldwide ENIGMA study
Schizophrenia is a prototypical network disorder with widespread brain-morphological alterations, yet it remains unclear whether these distributed alterations robustly reflect the underlying network layout. We tested whether large-scale structural alterations in schizophrenia relate to normative structural and functional connectome architecture, and systematically evaluated robustness and generalizability of these network-level alterations. Leveraging anatomical MRI scans from 2439 adults with schizophrenia and 2867 healthy controls from 26 ENIGMA sites and normative data from the Human Connectome Project (n = 207), we evaluated structural alterations of schizophrenia against two network susceptibility models: (i) hub vulnerability, which examines associations between regional network centrality and magnitude of disease-related alterations; (ii) epicenter mapping, which identifies regions whose typical connectivity profile most closely resembles the disease-related morphological alterations. To assess generalizability and specificity, we contextualized the influence of site, disease stages, and individual clinical factors and compared network associations of schizophrenia with that found in affective disorders. Our findings show schizophrenia-related cortical thinning is spatially associated with functional and structural hubs, suggesting that highly interconnected regions are more vulnerable to morphological alterations. Predominantly temporo-paralimbic and frontal regions emerged as epicenters with connectivity profiles linked to schizophrenia's alteration patterns. Findings were robust across sites, disease stages, and related to individual symptoms. Moreover, transdiagnostic comparisons revealed overlapping epicenters in schizophrenia and bipolar, but not major depressive disorder, suggestive of a pathophysiological continuity within the schizophrenia-bipolar-spectrum. In sum, cortical alterations over the course of schizophrenia robustly follow brain network architecture, emphasizing marked hub susceptibility and temporo-frontal epicenters at both the level of the group and the individual. Subtle variations of epicenters across disease stages suggest interacting pathological processes, while associations with patient-specific symptoms support additional inter-individual variability of hub vulnerability and epicenters in schizophrenia. Our work outlines potential pathways to better understand macroscale structural alterations, and inter- individual variability in schizophrenia
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