Nevin Manimala

PLoS One. 2021 Oct 8;16(10):e0258215. doi: 10.1371/journal.pone.0258215. eCollection 2021.

ABSTRACT

Agricultural index insurance contracts increasingly use remote sensing data to estimate losses and determine indemnity payouts. Index insurance contracts inevitably make errors, failing to detect losses that occur and issuing payments when no losses occur. The quality of these contracts and the indices on which they are based, need to be evaluated to assess their fitness as insurance, and to provide a guide to choosing the index that best protects the insured. In the remote sensing literature, indices are often evaluated with generic model evaluation statistics such as R2 or Root Mean Square Error that do not directly consider the effect of errors on the quality of the insurance contract. Economic analysis suggests using measures that capture the impact of insurance on the expected economic well-being of the insured. To bridge the gap between the remote sensing and economic perspectives, we adopt a standard economic measure of expected well-being and transform it into a Relative Insurance Benefit (RIB) metric. RIB expresses the welfare benefits derived from an index insurance contract relative to a hypothetical contract that perfectly measures losses. RIB takes on its maximal value of one when the index contract offers the same economic benefits as the perfect contract. When it achieves none of the benefits of insurance it takes on a value of zero, and becomes negative if the contract leaves the insured worse off than having no insurance. Part of our contribution is to decompose this economic well-being measure into an asymmetric loss function. We also argue that the expected well-being measure we use has advantages over other economic measures for the normative purpose of insurance quality ascertainment. Finally, we illustrate the use of the RIB measure with a case study of potential livestock insurance contracts in Northern Kenya. We compared 24 indices that were made with 4 different statistical models and 3 remote sensing data sources. RIB for these indices ranged from 0.09 to 0.5, and R2 ranged from 0.2 to 0.51. While RIB and R2 were correlated, the model with the highest RIB did not have the highest R2. Our findings suggest that, when designing and evaluating an index insurance program, it is useful to separately consider the quality of a remote sensing-based index with a metric like the RIB instead of a generic goodness-of-fit metric.

PMID:34624022 | DOI:10.1371/journal.pone.0258215

PLoS Comput Biol. 2021 Oct 8;17(10):e1009432. doi: 10.1371/journal.pcbi.1009432. Online ahead of print.

ABSTRACT

Measuring the activity of neuronal populations with calcium imaging can capture emergent functional properties of neuronal circuits with single cell resolution. However, the motion of freely behaving animals, together with the intermittent detectability of calcium sensors, can hinder automatic monitoring of neuronal activity and their subsequent functional characterization. We report the development and open-source implementation of a multi-step cellular tracking algorithm (Elastic Motion Correction and Concatenation or EMC2) that compensates for the intermittent disappearance of moving neurons by integrating local deformation information from detectable neurons. We demonstrate the accuracy and versatility of our algorithm using calcium imaging data from two-photon volumetric microscopy in visual cortex of awake mice, and from confocal microscopy in behaving Hydra, which experiences major body deformation during its contractions. We quantify the performance of our algorithm using ground truth manual tracking of neurons, along with synthetic time-lapse sequences, covering a wide range of particle motions and detectability parameters. As a demonstration of the utility of the algorithm, we monitor for several days calcium activity of the same neurons in layer 2/3 of mouse visual cortex in vivo, finding significant turnover within the active neurons across days, with only few neurons that remained active across days. Also, combining automatic tracking of single neuron activity with statistical clustering, we characterize and map neuronal ensembles in behaving Hydra, finding three major non-overlapping ensembles of neurons (CB, RP1 and RP2) whose activity correlates with contractions and elongations. Our results show that the EMC2 algorithm can be used as a robust and versatile platform for neuronal tracking in behaving animals.

PMID:34624016 | DOI:10.1371/journal.pcbi.1009432

PLoS Comput Biol. 2021 Oct 8;17(10):e1009451. doi: 10.1371/journal.pcbi.1009451. Online ahead of print.

ABSTRACT

Recent advances in two-photon fluorescence microscopy (2PM) have allowed large scale imaging and analysis of blood vessel networks in living mice. However, extracting network graphs and vector representations for the dense capillary bed remains a bottleneck in many applications. Vascular vectorization is algorithmically difficult because blood vessels have many shapes and sizes, the samples are often unevenly illuminated, and large image volumes are required to achieve good statistical power. State-of-the-art, three-dimensional, vascular vectorization approaches often require a segmented (binary) image, relying on manual or supervised-machine annotation. Therefore, voxel-by-voxel image segmentation is biased by the human annotator or trainer. Furthermore, segmented images oftentimes require remedial morphological filtering before skeletonization or vectorization. To address these limitations, we present a vectorization method to extract vascular objects directly from unsegmented images without the need for machine learning or training. The Segmentation-Less, Automated, Vascular Vectorization (SLAVV) source code in MATLAB is openly available on GitHub. This novel method uses simple models of vascular anatomy, efficient linear filtering, and vector extraction algorithms to remove the image segmentation requirement, replacing it with manual or automated vector classification. Semi-automated SLAVV is demonstrated on three in vivo 2PM image volumes of microvascular networks (capillaries, arterioles and venules) in the mouse cortex. Vectorization performance is proven robust to the choice of plasma- or endothelial-labeled contrast, and processing costs are shown to scale with input image volume. Fully-automated SLAVV performance is evaluated on simulated 2PM images of varying quality all based on the large (1.4×0.9×0.6 mm3 and 1.6×108 voxel) input image. Vascular statistics of interest (e.g. volume fraction, surface area density) calculated from automatically vectorized images show greater robustness to image quality than those calculated from intensity-thresholded images.

PMID:34624013 | DOI:10.1371/journal.pcbi.1009451

J Occup Environ Med. 2021 Oct 7. doi: 10.1097/JOM.0000000000002411. Online ahead of print.

ABSTRACT

OBJECTIVE: There is a scarcity of data on the impact of the pandemic in farmers.

METHODS: Cross-sectional survey of certified organic producers through a 28-item self-reported paper or electronic survey. Analysis included descriptive statistics, Cronbach α to measure the internal consistency of a six-item prevention scale, and correlation and regression analyses.

RESULTS: A total of 344 records were computed. Infection rate among producers was 6.4%. Sex and farm size were the most statistically significant predictors of prevention behaviors. Women reported more use of prevention methods (β = 0.333, P < 0.001) and those with 50 or more certified organic acres reporting less use of prevention methods (β = -0.228, P < 0.001). Mask wearing was significantly related to lower COVID-19 prevalence.

CONCLUSIONS: Determining prevalence and understanding how farmers follow prevention behaviors is essential for health care and public health interventions and policies.

PMID:34623976 | DOI:10.1097/JOM.0000000000002411

JMIR Med Inform. 2021 Sep 10. doi: 10.2196/30467. Online ahead of print.

ABSTRACT

BACKGROUND: In 2020, the COVID-19 pandemic put the world in crisis on both physical and psychological health. Simultaneously, a myriad of unverified information flowed on social media and online outlets. The situation was so severe that the World Health Organization identified it as an infodemic in February 2020.

OBJECTIVE: We want to study the propagation patterns and textual transformation of COVID-19 related rumors on a closed-platform.

METHODS: We obtained a dataset of suspicious text messages collected on Taiwan’s most popular instant messaging platform, LINE, between January and July 2020. We proposed a Classification-based Clustering algorithm that could efficiently cluster messages into groups, with each group representing a rumor. For ease of understanding, a group is referred to as a “rumor group”. Messages in a rumor group could be identical or within limited textual differences with one another. Therefore, each message in a rumor group is a form of the rumor.

RESULTS: A total of 936 rumor groups with at least 10 messages were discovered among 114,124 text messages collected from LINE. Among 936 rumors, 396 (42.3%) were related to COVID-19. Of 396 COVID-related rumors, 134 (33.8%) had been fact-checked by IFCN-certified agencies in Taiwan to be false or misleading. Studying the prevalence of Simplified Chinese characters or phrases that originated in China in the messages, we found that COVID-related messages, compared to non-COVID-related messages, were more likely to have been written by non-Taiwanese. The association was statistically significant with p < .01 by the chi-squared independence test. The qualitative investigations of the 3 most popular COVID-19 rumors revealed that key authoritative figures, mostly medical personnel, were often misquoted in the messages. In addition, these rumors resurfaced multiple times after being fact-checked, usually preceded by major societal events or textual transformations.

CONCLUSIONS: To fight infodemic, it is crucial that we first understand why and how a rumor becomes popular. While social media gives rise to an unprecedented number of unverified rumors, it also provides a unique opportunity for us to study rumor propagations and the interactions with society. Therefore, we must put more effort in the areas.

PMID:34623954 | DOI:10.2196/30467

Sci Total Environ. 2021 Sep 7;804:150151. doi: 10.1016/j.scitotenv.2021.150151. Online ahead of print.

ABSTRACT

We measured SARS-CoV-2 RNA load in raw wastewater in Attica, Greece, by RT-qPCR for the environmental surveillance of COVID-19 for 6 months. The lag between RNA load and pandemic indicators (COVID-19 hospital and intensive care unit (ICU) admissions) was calculated using a grid search. Our results showed that RNA load in raw wastewater is a leading indicator of positive COVID-19 cases, new hospitalization and admission into ICUs by 5, 8 and 9 days, respectively. Modelling techniques based on distributed/fixed lag modelling, linear regression and artificial neural networks were utilized to build relationships between SARS-CoV-2 RNA load in wastewater and pandemic health indicators. SARS-CoV-2 mutation analysis in wastewater during the third pandemic wave revealed that the alpha-variant was dominant. Our results demonstrate that clinical and environmental surveillance data can be combined to create robust models to study the on-going COVID-19 infection dynamics and provide an early warning for increased hospital admissions.

PMID:34623953 | DOI:10.1016/j.scitotenv.2021.150151

Cancer Control. 2021 Jan-Dec;28:10732748211045275. doi: 10.1177/10732748211045275.

ABSTRACT

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has overwhelmed the capacity of healthcare systems worldwide. Cancer patients, in particular, are vulnerable and oncology departments drastically needed to modify their care systems and established new priorities. We evaluated the impact of SARS-CoV-2 on the activity of a single cancer center.

METHODS: We performed a retrospective analysis of (i) volumes of oncological activities (2020 vs 2019), (ii) patients’ perception rate of the preventive measures, (iii) patients’ SARS-CoV-2 infections, clinical signs thereof, and (iv) new diagnoses made during the SARS-CoV-2 pandemic.

RESULTS: As compared with a similar time frame in 2019, the overall activity in total numbers of outpatient chemotherapy administrations and specialist visits was not statistically different (P = .961 and P = .252), while inpatient admissions decreased for both medical oncology and thoracic oncology (18% (P = .0018) and 44% (P < .0001), respectively). Cancer diagnosis plummeted (-34%), but no stage shift could be demonstrated.Acceptance and adoption of hygienic measures was high, as measured by a targeted questionnaire (>85%). However, only 46.2% of responding patients regarded telemedicine, although widely deployed, as an efficient surrogate to a consultation.Thirty-three patients developed SARS-CoV-2, 27 were hospitalized, and 11 died within this time frame. These infected patients were younger, current smokers, and suffered more comorbidities.

CONCLUSIONS: This retrospective cohort analysis adds to the evidence that continuation of active cancer therapy and specialist visits is feasible and safe with the implementation of telemedicine. These data further confirm the impact of SARS-CoV-2 on cancer care management, cancer diagnosis, and impact of infection on cancer patients.

PMID:34623943 | DOI:10.1177/10732748211045275

Cent Eur J Public Health. 2021 Sep;29(3):223-229. doi: 10.21101/cejph.a6697.

ABSTRACT

OBJECTIVES: Socioeconomic status (SES) and lifestyle have impact on recovery after ischaemic stroke (IS) and on risk of recurrent ischaemic stroke (RIS) in elderly patients. With regard to currently available limited data on young people, we aimed to assess SES and parameters of lifestyle and evaluate their relationship to stroke recovery and risk of RIS in young patients.

METHODS: We analysed consecutive young IS patients < 50 years enrolled in the prospective HISTORY (Heart and Ischaemic STrOke Relationship studY) study registered on ClinicalTrials.gov (NCT01541163). Data were acquired from structured a self-evaluating multiple-choice questionnaire. Clinical outcome was assessed using the Modified Rankin Scale (MRS) after 3 months with score 0-1 for excellent outcome.

RESULTS: Data were obtained from 297 (163 males, mean age 39.6 ± 7.8 years) young patients. Patients with MRS 0-1 (237, 79.8%) did not differ in SES except university education (21.1 vs. 3.3%; p = 0.001), less smoked (16.5 vs. 58.3%; p < 0.001), more of them did regular sport activities (79.1 vs. 51.6%; p = 0.02) and passed regular preventive medical checks (45.6 vs. 24.2%; p = 0.01). Twelve (4%) patients suffered from RIS during a follow-up with median of 25 months. They did not differ in SES but had higher body mass index (31.6 vs. 26.7; p = 0.007), reported less regular sport activities (16.7 vs. 73.0%; p < 0.001) and less regular medical checks (8.3 vs. 40.0%; p = 0.001).

CONCLUSION: In young patients, SES had no relationship to clinical outcome after IS and to risk of RIS except education level. Some parameters of health lifestyle were presented more in patients with excellent outcome and without RIS during the follow-up.

PMID:34623123 | DOI:10.21101/cejph.a6697

Cent Eur J Public Health. 2021 Sep;29(3):201-208. doi: 10.21101/cejph.a6813.

ABSTRACT

OBJECTIVES: Virtually no previous research assessed physical activity (PA) of university students in Finland, and their associations with depressive symptoms, whilst simultaneously controlling for potential confounders.

METHODS: Students at the University of Turku (1,177) completed an online health and wellbeing questionnaire that assessed depressive symptoms (22 items), as well as their achievement of the guidelines of four forms of low, moderate, vigorous, and muscle strengthening PA (LPA, MPA, VPA, MSPA, respectively). We explored the associations of depressive symptoms with these PA forms, accounting for socio-demographic and health confounders (age, gender, year of study, marital status, accommodation during semesters, self-rated health).

RESULTS: Achievement of PA guidelines was generally low for these young adult Finnish undergraduates. Bivariate relationships (no controlling for confounders) between depressive symptoms and four forms of PA guidelines achievement showed that in males, good/very good/excellent self-rated health, and achievement of the MSPA guidelines were significantly negatively associated with depressive symptoms. Conversely, low PA was significantly positively associated with depressive symptoms. Multiple regression (controlling for confounders) showed that achievement of the MSPA guidelines was independently significantly negatively associated with depressive symptoms; and whilst achievement of the MPA and VPA guidelines was negatively associated with depressive symptoms, the relationships did not reach statistical significance. Likewise, low PA was positively associated with depressive symptoms, but the relationships were again not statistically significant.

CONCLUSION: Universities would benefit from multipronged strategies and approaches employing effective interventions aimed at improving students’ general awareness of their health and promoting more physically active lifestyles among students.

PMID:34623120 | DOI:10.21101/cejph.a6813

Cent Eur J Public Health. 2021 Sep;29(3):195-200. doi: 10.21101/cejph.a6692.

ABSTRACT

OBJECTIVES: Mental stress, low health literacy (HL) and nutrition literacy (NL) are associated with serious negative health outcomes. The aim of this study was to investigate HL and NL levels, in relation to levels of perceived stress, in adults.

METHODS: This cross-sectional study was conducted in the urban area of the Attica region, Greece. The sample consisted of 1,281 individuals, aged ≥ 18 years. The European Health Literacy Questionnaire 47, the Greek version of the Nutrition Literacy Scale and the Perceived Stress Scale 14 were used. Socio-demographic characteristics were also assessed. Nonparametric Mann-Whitney U and Kruskal-Wallis tests, Pearson chi-square and multiple linear regression models were used.

RESULTS: The sample’s perceived stress mean value (SD) was 26.47 (7.27) with women scoring statistically significantly higher than men. The mean HL and NL scores were 32.28 (8.28) and 22.11 (5.67), respectively. Linear regression analysis has shown that perceived stress was significantly negatively associated with HL (p < 0.001) but not with NL levels (p = 0.675) after adjusting for a series of confounding variables.

CONCLUSIONS: Low health literacy seems to be very significantly associated with high levels of perceived stress. The reasons behind this association require further investigation.

PMID:34623119 | DOI:10.21101/cejph.a6692