Tag: statistics

Neuro Endocrinol Lett. 2021 May 4;42(2):70-80. Online ahead of print.

ABSTRACT

BACKGROUND: Sectional image of the peripheral nerves is a prerequisite for studying the morphological parameters of fascicular groups. Ultra-high precision MicroCT scan can explicitly display the internal morphology of physiological tissues. This study aimed to quantitatively measure the basic morphological parameters of fascicular groups of a peripheral nerve on MicroCT images, obtain the statistical principles and investigate the variation pattern of these morphological parameters during the process of fascicular group extension.

METHODS: Peripheral nerve specimens were processed with fat removal, decellularization, freezing, and drying, etc. The morphological parameters including area, perimeter, and the degree of circularity of each fascicular group in the peripheral nerve on MicroCT images were obtained by the image processing method. The cross-sectional area, cross-sectional perimeter, and cross-sectional degree of circularity of the single fascicular group were analyzed. Correlation between the cross-sectional area of single fascicular group and fascicular group extension, the correlation between the perimeter of cross-sectional single fascicular group and fascicular group extension, and correlation between the cross-sectional degree of circularity of single fascicular group and fascicular group extension were analyzed.

RESULTS: The cross-sectional area of fascicular groups confirmed the Beta distribution with a dominant proportion of small-area fascicular groups and a low percentage of large-area fascicular groups. Within the range of 3 mm, no significant correlation was observed between the cross-sectional area and the spatial extension of fascicular groups. The perimeter of the fascicular group section was normally distributed. The perimeter of the fascicular group section that did not remain stable immediately after the fascicular group – was split or merged, but it gradually became stable after the fascicular groups extended to a certain distance. The cross-sectional area of the fascicular groups did not change significantly during this period. The degree of circularity of the fascicular group section followed the t distribution pattern with scale/position parameters. Similarly, it gradually approached the average value only after the fascicular groups extended to a certain length.

CONCLUSION: Current study revealed the general rules of the basic morphometric parameters of fascicular groups in the process of spatial extension, which provided a pivotal basis for the repair of peripheral nerves and the diagnosis and treatment of neurological diseases and was of academic value and significance.

PMID:34217163

Neuro Endocrinol Lett. 2021 May 4;42(2):81-86. Online ahead of print.

ABSTRACT

OBJECTIVES: To investigate the effect of short-term spinal cord electrical stimulation (stSCS) on postherpetic neuralgia (PHN) and its effect on sleep quality in patients in Guangxi, China.

MATERIAL AND METHODS: 160 patients with acute PHN patients were divided into a control group and an experimental group according to the random number table method, 80 cases each. The experimental group was implanted with percutaneous epidural electrodes and given short-term spinal cord electrical stimulation treatment, while the control group was treated with nerve block therapy to compare the efficacy and sleep quality of the two groups of patients in different periods. Pain Visual Analogue Scale (VAS) score and Pittsburgh Sleep Quality Index (PSQI) were used to evaluate the analgesic effect and sleep quality, respectively.

RESULTS: The patients in the experimental group had significantly lower visual analog scale (VAS) scores and Pittsburgh Sleep Quality Index (PSQI) scores at 1, 2, 3 d, 1 week, and 1 and 3 months after treatment than those in the control group [after treatment 3 months: (0.86±0.31) points to (2.97±0.55) points, (5.4±1.16) score to (7.46±1.27) score], the difference was statistically significant (both P<0.05), and VAS and PSQI scores of the two groups showed a significant downward trend with the increase of treatment time.

CONCLUSION: The clinical effect of short-term spinal cord electrical stimulation on PHN is good, and it can play a rapid and effective relief effect on pain in patients. At the same time, it will effectively improve patient’s sleep quality, with high safety.

PMID:34217164

Psychiatry Res. 2021 Jun 20;303:114068. doi: 10.1016/j.psychres.2021.114068. Online ahead of print.

ABSTRACT

It is known that among those seeking to cease consumption of alcohol, there can be as high as a 50% relapse rate in the first 12 months. Different tools for treatments have been developed, such as telehealth, with the aim of helping this population. As a result of this demand, technology has gained strength in recent years. A new point of view about the treatment will broaden our knowledge far beyond just efficacy. It seems that understanding the mechanisms that lead to treatment success is as important as knowing its effectiveness. Therefore, the present study examined the relationships between Brief Motivational Intervention by telephone (BMI), motivational stage, outcome, and coping strategies using path analysis. In the post-evaluation, variables such as BMI (randomized individuals), motivational stage and decreased consumption of alcohol reached statistical significance (p<.001), suggesting that BMI might improve motivational stage and reduced consumption of alcohol. In terms of coping, the results also indicate that positive thinking might be a variable of interest when planning to decrease alcohol consumption. More research is needed to recognize the potential of new technology in the health area and to uncover the innumerable possibilities of using these tools as a strategy to help alcohol users.

PMID:34217102 | DOI:10.1016/j.psychres.2021.114068

Epidemics. 2021 Jun 24;36:100468. doi: 10.1016/j.epidem.2021.100468. Online ahead of print.

ABSTRACT

The natural history of human papillomavirus (HPV) from infection to cervical cancer differs between HPV types. Accordingly, type-specific natural history parameters are crucial for the mathematical models used to optimize the nearly life-long series of disease prevention measures. These parameters are estimated from genotyped data from trials and population level screening programs, typically one type at a time, which requires projecting the multiple-type data to the single type. To analyze impacts of such projection methods on the estimates, we compared estimating one type at a time using different projection methods with estimating all types together. We simulated genotyped data with chosen parameter values for two HPV types and analyzed the identifiability of the chosen values using the different estimation methods. We found the success of estimating one type at a time to be excessively sensitive to the data projection method, with potential to falsely identify the parameters at wrong values. Estimating all types together identified the parameters well. Our results were consistent both when trial and population level data were used. In conclusion, the potential confounding by multi-type infections has to be considered when choosing an estimation method for type-specific natural history parameters.

PMID:34217104 | DOI:10.1016/j.epidem.2021.100468

Plant Physiol Biochem. 2021 Jun 19;166:770-776. doi: 10.1016/j.plaphy.2021.06.013. Online ahead of print.

ABSTRACT

Fatty acid composition in the peel of four blood orange cultivars (‘Moro’, ‘Tarocco’, ‘Sanguinello’, and ‘Sanguine’) was identified and quantified by gas chromatography-mass spectrometry (GC-MS), in order to find its correlation with chilling susceptibility at harvest time and after 180 days of storage at 2 and 5 °C (2 days at 20 °C for shelf life). Twelve fatty acids were detected including 6 saturated (SFA) and 6 unsaturated (UFA), from which 4 monounsaturated (MUFA) and 2 polyunsaturated (PUFA) fatty acids occurred. The major fatty acids were palmitic, linoleic, and linolenic acids. The chilling injury (CI) index was significantly higher at 2 than 5 °C for all cultivars, with ‘Sanguinello’ being the more tolerant cultivar. The multivariate statistical analyses showed that ‘Sanguinello’ had the highest UFA, UFA/SFA ratio, and the lowest SFA, while ‘Moro’ as a cold sensitive cultivar had the highest SFA, the lowest UFA, and UFA/SFA ratio. Our findings revealed that the higher level of PUFAs (linoleic and linolenic acids) and enhancement of the UFA/SFA ratio are considered the most main adaptive mechanism under low temperatures of storage.

PMID:34217133 | DOI:10.1016/j.plaphy.2021.06.013

Sci Total Environ. 2021 Jun 18;794:148491. doi: 10.1016/j.scitotenv.2021.148491. Online ahead of print.

ABSTRACT

Biocrusts are an essential soil surface cover at drylands where ecosystems are especially fragile to soil degradation processes due to climatic peculiarities. In the present work, (micro)biological and physicochemical properties indicative of soil functionality were studied in two different biocrust types dominated by Dipolschistes diacapsis and Lepraria isidiata and in underlying soil at two different depths (SL1, soil layer right below the biocrusts, and SL2, soil layer underlying SL1) at the Tabernas desert (southeast Spain). The influence of climatic factors (rainfall and temperature) and general soil properties on the (micro)biological properties were also analyzed in different environmental (climatic) conditions over a period of two years. PERMANOVA analyses showed significant statistical differences (Pseudo-F = 63.9; P (perm) = 0.001) among biocrust and soil layers. Throughout the study period, enzyme activities involved in C, N, and P cycles; microbial biomass-C; basal respiration; and several properties directly related to ecosystem productivity (total organic carbon, total nitrogen, concentration of ammonium and nitrate) were higher in both biocrust types than in the underlying soil layers, showing that biocrusts improved soil functions related to nutrient cycling. These properties progressively diminished in successive soil layers under the biocrusts (biocrusts > SL1 > SL2). Biocrusts showed greater similarity to each other and to SL1 than to SL2 in (micro)biological properties. A distance-based linear model analysis showed that total organic carbon, rainfall, pH, mineralized N-NH₄⁺, and total nitrogen were the most important variables for predicting (micro)biological soil properties in biocrusts. Different biochemical behavior between the biocrusts and successive underlying soil layers has been found in wet periods. After rainfall periods, the biocrusts showed important peaks in basal soil respiration and in enzyme activities involved in C and P cycles. Nevertheless, soil biochemical properties hardly showed any peak in SL1 and did not change in SL2 despite soil moisture being higher in the soil layers below the biocrusts. Correlation analyses corroborated the existence of different relationships between soil moisture and enzymatic activities. In biocrusts, soil moisture showed a greater number of significant positive correlations with enzymes such as β-glucosidase, invertase, and phosphomonoesterase among others, whereas in SL1 it was only correlated with cellulase and in SL2 with dehydrogenase. A change in rainfall regime, as predicted by models based on climate change in arid and semiarid zones, could affect the activity of soil enzymes in the biocrusts and underlying layers, thus aggravating the degradation of these fragile dryland ecosystems.

PMID:34217081 | DOI:10.1016/j.scitotenv.2021.148491

Sci Total Environ. 2021 Jun 26;794:148718. doi: 10.1016/j.scitotenv.2021.148718. Online ahead of print.

ABSTRACT

Amazonia experienced unusually devastating fires in August 2019, leading to huge regional and global environmental and economic losses. The increase in fires has been largely attributed to anthropogenic deforestation, but anomalous climate conditions could also have contributed. This study investigates the climate influence on Amazonia fires in August 2019 and underlying mechanisms, based on statistical correlation and multiple linear regression analyses of 2001-2019 satellite-based fire products and multiple observational or reanalyzed climate datasets. Positive fire anomalies in August 2019 were mainly located in southern Amazonia. These anomalies were mainly driven by low precipitation and relative humidity, which increased fuel dryness and contributed to 38.9 ± 9.5% of the 2019 anomaly in pyrogenic carbon emissions over the southern Amazonia. The dry conditions were associated with southerly wind anomalies over southern Amazonia that suppressed the climatological southward transport of water vapor originating from the Atlantic. The southerly wind anomalies were caused by the combination of a Gill-type cyclonic response to the warmer North Atlantic sea surface temperature (SST), and enhancement of the Walker and Hadley circulations over South America due to the colder SST in the eastern Pacific, and a mid-latitude wave train triggered by the warmer condition in the western Indian Ocean. Our study highlights, for the first time, the important role of Indian Ocean SST for fires in Amazonia. It also reveals how cold SST anomalies in the tropical eastern Pacific link the warm phase of the El Niño-Southern Oscillation (ENSO) in the preceding December-January to the dry-season fires in Amazonia. Our findings can develop theoretical basis of global tropical SST-based fire prediction, and have potential to improve prediction skill of extreme fires in Amazonia and thus to take steps to mitigate their impacts which is urgency given that dry conditions led to the extreme fires are becoming common in Amazonia.

PMID:34217088 | DOI:10.1016/j.scitotenv.2021.148718

Vision Res. 2021 Jun 30;187:55-65. doi: 10.1016/j.visres.2021.06.007. Online ahead of print.

ABSTRACT

Visual texture, defined by local image statistics, provides important information to the human visual system for perceptual segmentation. Second-order or spectral statistics (equivalent to the Fourier power spectrum) are a well-studied segmentation cue. However, the role of higher-order statistics (HOS) in segmentation remains unclear, particularly for natural images. Recent experiments indicate that, in peripheral vision, the HOS of the widely adopted Portilla-Simoncelli texture model are a weak segmentation cue compared to spectral statistics, despite the fact that both are necessary to explain other perceptual phenomena and to support high-quality texture synthesis. Here we test whether this discrepancy reflects a property of natural image statistics. First, we observe that differences in spectral statistics across segments of natural images are redundant with differences in HOS. Second, using linear and nonlinear classifiers, we show that each set of statistics individually affords high performance in natural scenes and texture segmentation tasks, but combining spectral statistics and HOS produces relatively small improvements. Third, we find that HOS improve segmentation for a subset of images, although these images are difficult to identify. We also find that different subsets of HOS improve segmentation to a different extent, in agreement with previous physiological and perceptual work. These results show that the HOS add modestly to spectral statistics for natural image segmentation. We speculate that tuning to natural image statistics under resource constraints could explain the weak contribution of HOS to perceptual segmentation in human peripheral vision.

PMID:34217005 | DOI:10.1016/j.visres.2021.06.007

Neural Netw. 2021 Jun 25;143:368-376. doi: 10.1016/j.neunet.2021.06.020. Online ahead of print.

ABSTRACT

We study distributed learning for regularized least squares regression in a reproducing kernel Hilbert space (RKHS). The divide-and-conquer strategy is a frequently used approach for dealing with very large data sets, which computes an estimate on each subset and then takes an average of the estimators. Existing theoretical constraint on the number of subsets implies the size of each subset can still be large. Random sketching can thus be used to produce the local estimators on each subset to further reduce the computation compared to vanilla divide-and-conquer. In this setting, sketching and divide-and-conquer are complementary to each other in dealing with the large sample size. We show that optimal learning rates can be retained. Simulations are performed to compare sketched and non-standard divide-and-conquer methods.

PMID:34217064 | DOI:10.1016/j.neunet.2021.06.020

Vet Parasitol. 2021 Jun 26;296:109510. doi: 10.1016/j.vetpar.2021.109510. Online ahead of print.

ABSTRACT

Bovine ostertagiasis causes significant production losses to the cattle industry. Protective immunity induced by natural infection is slow to develop and anthelmintic resistance is rapidly developing. There is a need to advance alternatives for control of gastrointestinal nematode parasites. The present study investigated the effects of repeated, drug-truncated infections (rDTI) on development of protective immunity and attenuation of a challenge infection by O. ostertagi. Helminth-free calves were randomly assigned to either a rDTI or a control group (n = 5). The rDTI group received daily oral infections of 5000 Ostertagia L3 for 5 consecutive days, then were drug-treated on 14 and 15 days post infection (dpi), to attenuate O. ostertagi at the late fourth larval (L4) through young adult stages. DTI was repeated 3 weeks after the drug treatment. A total of 5 DTIs were administered to the DTI-treated animals. Non-DTI-treated, control animals received tap water as infection control. All animals were drug-treated at the same time. Animals were challenge-infected 4 weeks following the final round of rDTI. The results show that eggs per gram of feces (EPG) in the rDTI group were significantly reduced (P < 0.05) from 21 to 39 dpi, with an overall reduction in cumulative EPG. The control group exhibited reduced (P = 0.0564) average weight gains when compared to those of the rDTI group during weeks 4-5 post infection, a period coinciding with peak EPG output of control animals. Antigen-specific IgG, IgE and IgA responses were detected after the 2nd DTI, and stronger antibody recall responses were elicited by challenge infection. High levels of antigen-specific peripheral blood mononuclear cell (PBMC)/T cell proliferation to whole worm and excretory-secretory (ES) antigens were detected in rDTI-treated animals. These data indicate that partial protective immunity against ostertagiasis, involving cell-mediated and humoral responses, can be attained by rDTI which allowed for maximal antigen exposure from staggered parasitic developmental stages. The data suggest that rDTI can be used as a model to study host-parasite interactions and identify parasite antigens responsible for eliciting host protective immune responses.

PMID:34217073 | DOI:10.1016/j.vetpar.2021.109510