null response
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2021 ◽  
Author(s):  
Barbara Caimi ◽  
Marco Franzetti ◽  
Rossella Velleca ◽  
Alessia Lai ◽  
Antonella Gatti ◽  
...  

Abstract Background: The impact of coronavirus disease 2019 caused by Severe Acute Respiratory Syndrome Coronavirus 2 on hosts of Long Term Care Facilities (LTCFs) has been dramatic at global scale as aging and comorbitities pose individuals at increased risk of severe disease and death. Methods: Aim of this study was to evaluate SARS-CoV-2 S-IgG antibodies titers in 478 residents and 649 health care workers of the largest Italian nurse facility two months after the complete vaccination with BNT162B2. Associations among host-related factors and predictors of humoral response were investigated. Results: By stratifying levels of humoral responses, we found that 62.1%, 21.6%, 12.1% and 4.2% of hosts has high (>1,000 BAU/ml), medium (101-1,000), low (1-100) and null (<1 BAU/mL) S-IgG titers, respectively. Hosts with previous COVID-19 and those with SARS-CoV-2 N-IgG positive serology showed higher level of serological response (p<0.001 and p<0.001, respectively), while the administration of corticosteroid or cancer diminished all levels of specific antibodies (p=0.019 and p=0.004). Significant associations were observed for these parameters in those with suboptimal response (p<0.001, p<0.001, p=0.028 and p=0.005) and with a null one (p=0.005, p<0.001 and p=0.039). Predictors of an increased risk of null response were advanced age, corticosteroid therapy and diabetes mellitus (p=0.025, p=0.017 and p=0.037). In contrast, previous diagnosis of COVID-19 resulted strongly associated with a reduced risk of null response to vaccination (p<0.001). Conclusions: SARS-CoV-2 specific antibodies in elderly individuals need to be measured to consider a third dose of vaccine after mass vaccination for prevention of reinfections in LTCFs despite the maintenance of barrier measures.


2021 ◽  
Author(s):  
Tamizharasan Kanagamani ◽  
V. Srinivasa Chakravarthy ◽  
Balaraman Ravindran

AbstractWe present a deep network-based model of the associative memory functions of the hippocampus. The proposed network architecture has two key modules: 1) an autoencoder module which represents the forward and backward projections of the cortico-hippocampal projections and 2) a module that computes familiarity of the stimulus and implements hill-climbing over the familiarity which represents the dynamics of the loops within the hippocampus. The proposed network is used in two simulation studies. In the first part of the study, the network is used to simulate image pattern completion by autoassociation under normal conditions. In the second part of the study, the proposed network is extended to a heteroassociative memory and is used to simulate picture naming task in normal and Alzheimer’s disease (AD) conditions. The network is trained on pictures and names of digits from 0 – 9. The encoder layer of the network is partly damaged to simulate AD conditions. As in case of AD patients, under moderate damage condition, the network recalls superordinate words (“odd” instead of “nine”). Under severe damage conditions, the network shows a null response (“I don’t know”). Neurobiological plausibility of the model is extensively discussed.


2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Mohamed Abd Alla ◽  
ahmed altambouly ◽  
Mohamed Abd Alla ◽  
Galal AbuFarrag ◽  
Islam Ammar ◽  
...  

2020 ◽  
Author(s):  
Luca Morelli ◽  
Sandi Paulišić ◽  
Wen-Ting Qin ◽  
Irma Roig-Villanova ◽  
Manuel Rodriguez-Concepcion ◽  
...  

SUMMARYWhen growing in search for light, plants can experience continuous or occasional shading by other plants. Plant proximity causes a decrease in the ratio of red to far red light (low R:FR) due to the preferential absorbance of red light and reflection of far red light by photosynthetic tissues of neighboring plants. This signal is often perceived before actual shading causes a reduction in photosynthetically active radiation (low PAR).Here we investigated elongation, photosynthesis and photoacclimation responses in several Brassicaceae species to explore the possible connections between low R:FR and low PAR.A negative correlation was found in shade-tolerant Cardamine hirsuta and shade-avoider Arabidopsis thaliana seedlings (e.g., shade-tolerance was associated with a good adaptation to low PAR but a poor or null response to low R:FR exposure). However, they could be genetically uncoupled. Most interestingly, exposure to low R:FR of shade-avoider plants improved their photoacclimation to low PAR by triggering changes in photosynthesis-related gene expression, pigment accumulation and chloroplast ultrastructure.These results indicate that low R:FR signaling unleashes molecular, metabolic and developmental responses that allow shade-avoider plants (including most crops) to adjust their photosynthetic capacity in anticipation of eventual shading by nearby plants.


2020 ◽  
Vol 13 (6) ◽  
pp. 79
Author(s):  
D. B. Morais ◽  
M. S. Jesus ◽  
A. C. Bonatto ◽  
D. W. Silva ◽  
A. Kataoka

Anemia is defined as the presence of erythrocytes, hemoglobin concentration and/or hematocrit below the reference values, leading to death if not treated. It is manifested clinically in the presence of pale mucosae, dyspnea, exercise intolerance and increased heart rate due to reduced tissue oxygenation. The aim of this study was to classify the anemia according to the medullar response in regenerative with weak, moderate or intense release and non-regenerative with null response, correlating with its possible causes by reticulocyte count. Thus, 50 blood samples from anemic dogs treated at the Veterinary Hospital of the Universidade Federal de Mato Grosso, Sinop Campus, were evaluated. After collection, blood smears were prepared for reticulocyte counting using supravital staining. Of the 50 animals evaluated, 54% (27/50) showed non-regenerative anemia with null response (<60,000 cells/μL), 36% (18/50) showed regeneration with weak release (60,000 to 150,000 cells/μL) and 10% (5/50) presented moderate to intense regeneration (>150,000 cells/μL). In conclusion, in this study was observed a predominance of non-regenerative anemia and a lower incidence of responsive anemia; the medullary response was more evident in hemoparasitosis anemia and non-regenerative anemia occurred mainly in animals with renal insufficiency, possibly due to insufficient production of erythropoietin


Geophysics ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. J31-J41 ◽  
Author(s):  
Carlos Alberto Mendonça ◽  
William Pareshi Soares ◽  
Felipe Lisbona Cavalcante

Dike swarms are igneous structures of continental expression accounting for major episodes of magmatism in igneous provinces, mantle plume heads, and continental breakup. In regional magnetic maps, dike swarms are recognized by high-amplitude lineaments indicative of lengthy and juxtaposed magnetized bodies. High-anomaly amplitudes from such tabular (2D) bodies tend to obscure lower amplitude contributions from localized 3D sources, representative of magmatic structures that once served as magma plumbing and storage. The recognition of such subtle signals with conventional filtering techniques is prevented due to spectral overlapping of individual contributions. We have developed a processing scheme to remove contributions from elongated, homogeneous sources to make clear contributions from 3D sources located below, in the middle of, or above a framework of elongated homogeneous sources. The canceling of 2D fields is accomplished by evaluating the horizontal component of the magnetic anomaly along the lineament strike, which for true elongated and homogeneous sources gives a null response. The gradient intensity of the transformed field is then evaluated to enhance residual fields over 3D sources. Lineaments thus removed identify tabular bodies with homogeneous magnetization, interpreted as being indicative of the uniform distribution (mineral type, concentration, and grain-size distribution) of magnetic carrier content in the rock. We evaluated our technique with synthetic data from multiple 2D-3D interfering sources and then applied it to interpret airborne data from the Ponta Grossa Dike Swarm of the Paraná-Etendeka Magmatic Province in Southeastern Brazil.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Michael H Parsons ◽  
Michael A Deutsch ◽  
Dani Dumitriu ◽  
Jason Munshi-South

Abstract Wild rats (Rattus norvegicus) are among the most ubiquitous and consequential organisms in the urban environment. However, collecting data from city rats is difficult, and there has been little research to determine the influence, or valence, of rat scents on urban conspecifics. Using a mark-release-monitor protocol, we previously learned rats can be attracted to remote-sensing points when baited with mixed-bedding from male and female laboratory rats. It was thus essential that we disambiguate which scents were eliciting attraction (+ valence), inspection, a conditioned response whereby attraction may be followed by avoidance (–valence), or null-response (0 valence). We used radio-frequency identification tagging and scent-baited antennas to assess extended (>40 days) responses to either male or female scents against two risk presentations (near-shelter and exposed to predators). In response to male scents, rats (n = 8) visited both treatments (shelter, exposed) more than controls (0.2 visits/day treatment vs. 0.1/day; P < 0.05) indicating scents accounted for response more so than risk. Dwell-times, however, did not differ (1.2 s/visit treatment vs. 0.9 s/visit; P > 0.5). These outcomes are consistent with inspection (–valence). In response to female scents, rats (n = 7) increased visitation (5.02 visits/day vs. 0.1/day controls; P < 0.05), while dwell-times also increased 6.8 s/visit vs. 0.2 s/visit in both risk-settings. The latter is consistent with persistent attraction (+valence), but was also influenced by shelter, as runway visits (1.1 visits/day) were a magnitude more common than predator-exposed (0.1 visits/day). Further understanding and exploiting the mobility of city rats is necessary for improvements in basic and applied research, including city pathogen-surveillance and urban wildlife management.


2018 ◽  
Vol 36 (2) ◽  
pp. 126-134
Author(s):  
Manuel Iván Gómez ◽  
Stanislav Magnitskiy ◽  
Luis Ernesto Rodríguez

Potato yield depends on the genotype-environment interaction, edaphic nutrient supply, and fertilization rates. The total tuber yield (FWt), dry weight of tubers (DWt), harvest index (HI) and nutrient use efficiency in tubers (NUEt) were evaluated in the Andean region in Colombia at 75, 100, 125, and 150 d after sowing using two cultivars (Capiro, Suprema), three locations with contrasting soils (Subachoque, Facatativa and Choconta) and two levels of fertilization: F0 (unfertilized) and F1 (fertilized). The Humic Dystrudept soils with fertilization (Choconta) presented late tuber filling with increases of 48 and 64% for the DWt in the cvs. Suprema and Capiro, respectively. In Suprema, the highest production potentials were obtained in fertilized soils with low fertility, with increases of 60.9% for the DWt and 75% for the HI. On the other hand, Capiro was better adapted to soils with medium to high fertility, with increases of up to 86.7% for the FWt, as compared to the unfertilized soils. This increase may be related to higher rates of nutrient recovery efficiency (RFt), higher accumulated nutrients per tuber yield (EPt) and a better NUEt because N. Suprema presented a negative EPt and RFt with HI<45% and the lowest NUE of N and K in high fertility soils, which represents a null response to fertilization and possible mechanisms of luxury consumption for the evaluated elements.


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