bluuebunny/crossref_metadata_2025 huggingface dataset:
Farmer Knowledge in Potato Virus Epidemiology and Control in Kenya
Authors: Onditi John , Ng’anga Nancy , Nyongesa Moses , van der Vlugt René
Published: March 2021

Potato is an important food security crop in Kenya. High prevalence of potato viruses is one of the major causes of low potato yields. Implementation of effective virus management strategies requires information on farmers’ perceptions and practices on virus epidemiology and control. To better understand farmers’ knowledge and practices in virus control and set possible pathways for intervention, a household survey involving 147 respondents was conducted in two major potato-growing regions in Kenya. Lack of sufficient technical information on potato virus symptoms, vectors and modes of transmission was found to be the major hindrance to farmers’ efforts towards virus control. A spider diagram approach was therefore used to determine the aspect of virus control that required the highest prioritization for immediate intervention by policy makers. Use of virus-resistant cultivars was found to require the most urgent attention compared to other aspects of virus control and was expected to have greater impact in lowering virus prevalence. This study showed that enhancing farmer knowledge needs to be prioritised as this is a key determinant of the success of the virus control strategy to be selected for implementation.
Screening for PVYN-Wi Resistance in Kenyan Potato Cultivars
Authors: Onditi John , Nyongesa Moses , van der Vlugt René
Published: March 2021

Over the past decades, two new strains of potato virus Y (PVYN-Wi (Wilga) and PVYNTN) have been the most widely distributed worldwide in potato crops (Solanum tuberosum L.). Effective resistance genes comprehensive against all the known strains of the virus are available in some commercial cultivars. However, not all resistance genes in cultivars have been challenged by the new PVY strains to confirm effectiveness of the resistances available. This study was set to identify PVY resistant genotypes and estimate yield losses in potato cultivars in Kenya. PVYN-Wi was used for PVY resistance screening because it was the most prevalent strain in Kenya and also was found to produce more severe infection in Kenyan potato genotypes compared with PVYO (the second most prevalent strain). Three cultivars, Kenya Karibu, Sherekea and Unica, were identified as resistant because they did not get PVY infections over three seasons of both greenhouse and field screening experiments. In addition, two early generation breeding clones were identified as resistant at 28 days post-inoculation. In susceptible cultivars Dutch Robyjn, Nyayo and Kenya Mpya, PVYN-Wi infection caused yield losses of 21.6, 39.0 and 53.1%, respectively, after three seasons. This study demonstrated the necessity to screen for PVY resistance based on the most prevalent PVY strains and to make an informed decision on the usefulness of current levels of resistance in potato cultivars.
Seismotectonics and Spatio-temporal Variations in Seismicity Rates along Andaman Trench
Authors: Bhat Gulam Rasool , Iqbal Vazeem , Yousuf Maqbool , Wani Suhail
Published: March 2021

The earthquake Frequency Magnitude Distribution (FMD) or b values have been meticulously used in the last two decades as a deterministic earthquake precursor or indicator, in earthquake forecasting or probabilistic seismic hazard assessment studies, in a variety of tectonic and stress regimes. In the present study, temporal fluctuations of b values were analysed by means of 185 well located (Mw ≥ 5) earthquakes, in the region of Andaman and Nicobar Islands (N10° to 14°) for a time period of ~100 years (1918 to 2018). Variation in b value rates before and after the 2004 great Sumatra-Andaman earthquake (Mw 9.3) was analysed, preceded by a comprehensive geodynamic and seismotectonic-crustal deformation overview along the Andaman trench section. The analysis suggest a precursory drop in b values from 1.05 ± 0.05 (1918 to 2004) to 0.90 ± 0.05 post 2004 earthquake (2004 to 2018) reflecting a greater slip deficit and strain localization, that exceeds considerably the pattern of energy release in this region. Further, the region of Andaman and Nicobar Islands have witnessed a poor slip distribution (on-fault reactivation) from the great earthquakes that nucleated near the Sumatra segment, and have ruptured few large earthquakes, with no accounts of great earthquake (>Mw 8) during the last century. This emphasizes that, strain accumulation has been concentrated over a long period of time, and can contribute a destructive deformation event in near future.
New Finding of Silica-deficient Sapphirine-bearing Granulites from NNE of Suranganar Village, Southern Madurai Block, India
Authors: Rai Swapnil Kumar , Prakash Divya , Yadav Roopali , Jaiswal Srishti , Kumar R.S. , Singh Chandra Kant
Published: March 2021

An infrequent occurrence of sapphirine from metapelite rocks of the Cardamom hills of South India has been reported. This report of sapphirine may not be the first from the Southern Granulite Terrane (SGT) but is essentially from a new locality. The studied metapelites are silica-undersaturated devoid of garnet and the sapphirine symplectites. The symplectites of orthopyroxene + cordierite, orthopyroxene + K-feldspar + cordierite, orthopyroxene + sapphirine + cordierite ± K-feldspar ± biotite, orthopyroxene + biotite + cordierite + K-feldspar are discernible. The textural patterns show partial to complete pseudomorphism of the initially formed orthopyroxene and sapphirine and their succeeding decomposition to present stage. The relative XMg calculated for the key minerals show the trend as: Crd > Spr > Bt > Opx. The pseudosection modelling and the calculated P-T diagram drawn from the average bulk composition of the studied metapelite connote isothermal decompression with peak pressure and temperature conditions stable at ~10 Kbar and ~985 °C respectively. The assemblage reported in this study has an important bearing on the crustal evolution of the high-grade metamorphism exhumed from a deeper level of the crust.
First Fossil Legume Flower of Papilionoid Affinity from India
Authors: Hazra Taposhi , Hazra Manoshi , Bera Subir , Khan Mahasin Ali
Published: March 2021

Fabaceae, presently a significant dominant taxon of the tropical vegetation of India, has been recognized as the most widespread and common component of Indian Cenozoic flora and known from numerous fossil woods, leaflets, pollen, and fruits. However, unfortunately no fossil legume flower has been reported from the Cenozoic sediments of India so far. Here, for the first time an extinct papilionoid flower is documented from the latest Neogene (Pliocene: Rajdanda Formation) sediments of Chotanagpur Plateau, eastern India. The fossil flower is characterized by a long pedicel, five-lobed calyx, campanulate calyx tube with unequal calyx teeth, corolla with well-preserved standard and wing petal and is recognized as Neopapilionia indica Hazra, Hazra M and Khan gen. et sp. nov. The palaeoclimatic significance in terms of the present-day distribution of its modern analogue is also discussed.
Sediment and Nutrient Transfer from an Inter-montane Agricultural Catchment in Himachal Himalayas of Northwestern India
Authors: Singh Jagdeep , Singh Omvir
Published: March 2021

The present study aims to quantify the transfer of sediments and nutrients from an inter-montane agricultural catchment located in lower Himachal Himalayas of north western India. The study is based on long-term water quality data for July to September months for the period 2004 to 2010. The data for this study has been procured from Bhakra Beas Management Board, Sundernagar. The study has revealed a high degree of transfer and variability in sediment and nutrient concentrations, loads and yields, causing pollution downstream. The sediment concentrations have varied from 10 to 8117 mg/l with a variability of 54%. The micro nutrients concentrations have varied from 0.03 to 0.41 mg/l for zinc, 0.13 to 6.64 mg/l for iron and 0.02 to 1.30 mg/l for copper. Among the macro nutrients, highest concentrations have been observed for sulphate (11.81 mg/l) followed by phosphate (0.97 mg/l) and nitrate (0.40 mg/l). The correlation analysis has revealed that sediment and nutrient flux from the catchment are dependent on amount of stream flow. However, the extent of correlations has been, in general, low or non-significant. The findings of this study will have key implications for future sediment and nutrient transfer from agricultural catchments of north western Himalayan region.
Do Somatic Cells Really Sacrifice Themselves? Why an Appeal to Coercion May be a Helpful Strategy in Explaining the Evolution of Multicellularity
Authors: Stencel Adrian , Suárez Javier
Published: March 2021

An understanding of the factors behind the evolution of multicellularity is one of today’s frontiers in evolutionary biology. This is because multicellular organisms are made of one subset of cells with the capacity to transmit genes to the next generation (germline cells) and another subset responsible for maintaining the functionality of the organism, but incapable of transmitting genes to the next generation (somatic cells). The question arises: why do somatic cells sacrifice their lives for the sake of germline cells? How is germ/soma separation maintained? One conventional answer refers to inclusive fitness theory, according to which somatic cells sacrifice themselves altruistically, because in so doing they enhance the transmission of their genes by virtue of their genetic relatedness to germline cells. In the present article we will argue that this explanation ignores the key role of policing mechanisms in maintaining the germ/soma divide. Based on the pervasiveness of the latter, we argue that the role of altruistic mechanisms in the evolution of multicellularity is limited and that our understanding of this evolution must be enriched through the consideration of coercion mechanisms.
Reflecting on professional identity in undergraduate medical education: implementation of a novel longitudinal course
Authors: Désilets Valérie , Graillon Ann , Ouellet Kathleen , Xhignesse Marianne , St-Onge Christina
Published: March 2021

Background Today’s healthcare professionals face numerous challenges. Improving reflection skills has the potential to contribute to the better management of complex patients and healthcare systems, as well as to improve professional practice. However, the question of how reflection skills can inform professional identity development at the undergraduate medical education level remains unanswered.

Approach The authors developed and implemented a 4-year course that aims to engage students in a reflective process to increase their awareness of their professional identity development. The course is structured around three types of pedagogical activities: workshops, reflections deposited in an electronic portfolio, and individual discussions with mentors.

Evaluation Sixty-four 1st year students (33%) and 17 mentors (50%) from the 2017–2018 cohort completed evaluation questionnaires. For the 2018–2019 academic year, 73 1st year students (34%) and 27 2nd year students (14%), as well as 20 1st year (59%) and 19 2nd year mentors (57%) replied. Students and mentors considered that the pedagogical activities contributed to the development of students’ professional identity through the acquisition of reflection skills, but some elements were perceived as challenging, notably, completing the portfolio, finding a subject to reflect about and the timing of the proposed activities.

Reflection An important preoccupation when wanting to foster the development of professional identity through the acquisition of reflection skills is the authenticity of students’ reflection. We tried to favor authentic reflection, by having a mentee-mentor pair throughout the entire 4‑year course. A rigorous evaluation process helped us identify and promptly correct issues as they surfaced.
Comparison of mechanical and tribological properties of CrBN coatings modified by Ni or Cu incorporation
Authors: Wang Qianzhi , Jin Xuxin , Zhou Fei
Published: March 2021

To compare the merits of Ni and Cu, the mechanical and tribological properties of CrBN coatings modified by Ni or Cu incorporation were studied. The results demonstrated that the CrBN-Cu coatings presented a lower friction coefficient than CrBN and CrBN-Ni coatings owing to the improved lubrication effect of the CuO layer originating from the tribochemical reaction. However, the hardness decline due to Cu incorporation was much greater than that of Ni incorporation. Thus, the CrBN-Cu coatings exhibited a higher wear rate than the CrBN coating. In contrast, the plastic deformation enhancement induced by Ni incorporation exceeded the hardness decline. Therefore, the wear of CrBN-Ni coatings partially turned to plastic deformation to present a lower wear rate than that of the CrBN coating.
Farmers’ agricultural tractor preferences in Ethiopia: a choice experiment approach
Authors: Workneh Wubamlak Ayichew , Ujiie Kiyokazu , Matsushita Shusuke
Published: March 2021

Unless supported by agricultural mechanization, achieving sustainable development goals is generally challenging in sub-Saharan African countries, specifically so in Ethiopia. Animal power is the dominant mode for plowing, threshing, and transportation in Ethiopia and yet, at the same time little effort was employed to assess subsistence farmer’s tractor demand in the study area. This study was conducted to understand the preferences of wheat producer subsistence farmers for agricultural tractors in Ethiopia in 2017. A random sample of 79 households participated in either rental or purchase choice experiments. The descriptive statistics revealed that 42% of respondents chose to buy tractors, and 43% preferred to use rental services. The random parameter logit estimation result showed that plowing-and-transporting tractors were preferred by the farmers who participated in the purchase design. They are also willing to pay ETB 149,142 (USD 6516) for transporting-only tractors, ETB 218,253 (USD 9536) for plowing-only tractors, and ETB 367,957 (USD 16,077) for plowing-and-transport-only tractors. However, due to the exclusion of high wheat producers in the rent experiment, the current rental price was found to be far from the 99% confidence interval of the estimated price. The government should promote and encourage the appropriate use of agricultural tractors that are affordable for subsistence farmers through rental or purchase. Conservative agriculture should also be practiced as the over-use of tractors may disrupt biodiversity and natural biological process.
c-CSN: Single-Cell RNA Sequencing Data Analysis by Conditional Cell-Specific Network
Authors: Li Lin , Dai Hao , Fang Zhaoyuan , Chen Luonan
Published: March 2021

The rapid advancement of single-cell technologies has shed new light on the complex mechanisms of cellular heterogeneity. However, compared to bulk RNA sequencing (RNA-seq), single-cell RNA-seq (scRNA-seq) suffers from higher noise and lower coverage, which brings new computational difficulties. Based on statistical independence, cell-specific network (CSN) is able to quantify the overall associations between genes for each cell, yet suffering from a problem of overestimation related to indirect effects. To overcome this problem, we propose the c-CSN method, which can construct the conditional cell-specific network (CCSN) for each cell. c-CSN method can measure the direct associations between genes by eliminating the indirect associations. c-CSN can be used for cell clustering and dimension reduction on a network basis of single cells. Intuitively, each CCSN can be viewed as the transformation from less “reliable” gene expression to more “reliable” gene–gene associations in a cell. Based on CCSN, we further design network flow entropy (NFE) to estimate the differentiation potency of a single cell. A number of scRNA-seq datasets were used to demonstrate the advantages of our approach. 1) One direct association network is generated for one cell. 2) Most existing scRNA-seq methods designed for gene expression matrices are also applicable to c-CSN-transformed degree matrices. 3) CCSN-based NFE helps resolving the direction of differentiation trajectories by quantifying the potency of each cell. c-CSN is publicly available at https://github.com/LinLi-0909/c-CSN.
Npac Is a Co-Factor of Histone H3K36me3 and Regulates Transcriptional Elongation in Mouse Embryonic Stem Cells
Authors: Yu Sue , Li Jia , Ji Guanxu , Ng Zhen Long , Siew Jiamin , Lo Wan Ning , Ye Ying , Chew Yuan Yuan , Long Yun Chau , Zhang Wensheng , Guccione Ernesto , Loh Yuin Han , Jiang Zhi-Hong , Yang Henry , Wu Qiang
Published: March 2021

Chromatin modification contributes to pluripotency maintenance in embryonic stem cells (ESCs). However, the related mechanisms remain obscure. Here, we show that Npac, a “reader” of histone H3 lysine 36 trimethylation (H3K36me3), is required to maintain mouse ESC (mESC) pluripotency since knockdown of Npac causes mESC differentiation. Depletion of Npac in mouse embryonic fibroblasts (MEFs) inhibits reprogramming efficiency. Furthermore, our chromatin immunoprecipitation followed by sequencing (ChIP-seq) results of Npac reveal that Npac co-localizes with histone H3K36me3 in gene bodies of actively transcribed genes in mESCs. Interestingly, we find that Npac interacts with positive transcription elongation factor b (p-TEFb), Ser2-phosphorylated RNA Pol II (RNA Pol II Ser2P), and Ser5-phosphorylated RNA Pol II (RNA Pol II Ser5P). Furthermore, depletion of Npac disrupts transcriptional elongation of the pluripotency genes Nanog and Rif1. Taken together, we propose that Npac is essential for the transcriptional elongation of pluripotency genes by recruiting p-TEFb and interacting with RNA Pol II Ser2P and Ser5P.
Reducing the risk of cerebrospinal fluid rhinorrhea following translabyrinthine surgery of the posterior fossa
Authors: Cooper Matthew W. , Ward Bryan K. , Sharon Jeffery , Francis Howard W.
Published: March 2021

Objective

To describe the procedure and results of an adapted closure and reconstruction technique for translabyrinthine surgery that focuses on identifying and managing potential pathways for CSF egress to the middle ear and Eustachian tube.

Methods

Retrospective review of a cohort of translabyrinthine acoustic neuroma cases that were reconstructed using this technique.

Results

In addition to meticulous packing of potential conduits using soft tissue, hydroxyapatite cement is used to seal opened air cell tracts prior to obliteration of the mastoid defect using adipose tissue. Early results of a small patient cohort using this technique are encouraging and there were no wound infections. There was a single case of CSF rhinorrhea associated with incomplete sealing of opened petrous apex cells, with no recurrence after appropriate implementation of the described protocol during revision surgery.

Conclusion

Proactive management of potential conduits of CSF egress including opened air cell tracts has a high likelihood of reducing rates of rhinorrhea and need for revision surgery after the translabyrinthine approach to the posterior fossa.
What Happens to the Worried Well? Follow-Up of Subjective Cognitive Impairment
Authors: Sutherland Margaret , Kirk Andrew , Karunanayake Chandima P. , O’Connell Megan E. , Morgan Debra G.
Published: March 2021

Background:

Increasing concern around perceived neurocognitive decline is increasing the number of referrals to specialists and anxiety for patients. We aimed to explore the likelihood of the “worried well” experiencing neurocognitive decline and developing a neurological diagnosis.

Methods:

A total of 166 “worried well” patients who attended the Rural and Remote Memory Clinic (RRMC) between 2004 and 2019 were included in this study. Demographic, health, social, and behavioral factors were measured at the initial visit. Mini-Mental State Examination (MMSE), Center for Epidemiologic Studies Depression Scale (CESD), and Functional Activities Questionnaire (FAQ) scores were measured and compared at initial assessment and at 1-year follow-up. MMSE scores over time were assessed with a mean follow-up of 2.95 years (SD 2.87).

Results:

No statistically significant difference was seen in MMSE, CESD, or FAQ scores when comparing clinic day to 1-year follow-up, and no consistent pattern of MMSE score over time was seen. Of the 166 patients with subjective cognitive impairment (SCI) on initial assessment, 5 were diagnosed with Alzheimer’s disease (AD) at 8.5, 3.5, 5, 3, and 1.75 years; 2 were diagnosed with MCI at 1 and 2 years; 1 was diagnosed with vascular cognitive impairment at 5 years; and 1 was diagnosed with frontotemporal dementia (FTD) at 0.5 years.

Conclusion:

The likelihood of a patient with SCI developing a neurological diagnosis is reassuringly low (9/166), but not irrelevant. This, along with the benefits of early diagnosis and treatment for dementia, leads us to believe that patients with SCI should still be seen in follow-up at least at the 1-year mark.
GAS ION SOURCE PERFORMANCE OF THE ENVIRONMICADAS AT HEKAL LABORATORY, DEBRECEN, HUNGARY
Authors: Molnár Mihály , Mészáros Marianna , Janovics Róbert , Major István , Hubay Katalin , Buró Botond , Varga Tamás , Kertész Titanilla , Gergely Virág , Vas Ádám , Orsovszki Gergely , Molnár Anita , Veres Mihály , Seiler Martin , Wacker Lukas , Jull A J Timothy
Published: March 2021

A coupled accelerator mass spectrometer–gas interface system has been successfully operating at the Hertelendi Laboratory of Environmental Studies, Debrecen, Hungary, since 2013. Over the last 6 years more than 500 gas targets were measured below 100 µg carbon content for carbon isotopic composition. The system was tested with blanks, OxII, IAEA-C1, IAEA-C2, and IAEA-C7 standards. The performance of our instrumentation shows good agreement with other published gas-interface system data and also shows a quite good agreement with the nominal value of international standard samples. There is a measurable but quite small memory effect after modern samples, but this does not significantly affect the final results. Typical ion currents at the low energy side were between 10–15 µA with a 5% CO2 in He mixing ratio. The relative errors average ±6% for samples greater than or equal to 10 µgC sample with mean count rates of 300 counts per microgram C for OxII. The blank is comparable with other systems, which is 0.0050 ± 0.0018 F14C or 34,000–47,000 yr BP, which allows for the routine measurement of both of small environmental and archeological samples.
Effects of multiple stressors on northern leopard frogs in agricultural wetlands
Authors: Marcogliese David J. , King Kayla C. , Bates Kieran A.
Published: March 2021

Natural and anthropogenic stressors, including parasites and pesticides, may induce oxidative stress in animals. Measuring oxidative stress responses in sentinel species that are particularly responsive to environmental perturbations not only provides insight into host physiology but is also a useful readout of ecosystem health. Newly metamorphosed northern leopard frogs (Lithobates pipiens), a sentinel species, were collected from agricultural and non-agricultural wetlands exposed to varying concentrations of the herbicide atrazine. Significant effects of certain parasites' abundance and their interaction with atrazine exposure on frog oxidative stress were identified. Specifically, increased protein levels were detected in frogs infected with echinostome metacercariae. In addition, the nematodeOswaldocruziasp. was significantly associated with increased thiol concentration and catalase activity. Significant parasite × atrazine interactions were observed for atrazine exposure and the abundance ofOswaldocruziasp. on thiol, as thiol concentrations increased with parasite abundance at low atrazine localities and decreased in high atrazine wetlands. In addition, a significant interaction between the abundances ofOswaldocruziasp. and gorgoderid trematodes on thiol concentrations was observed. These findings demonstrate that studies of oxidative stress on animals in natural ecosystems should account for the confounding effects of parasitism, particularly for amphibians in agricultural landscapes.
THE SPECIFICITY OF EVENT EXPRESSION IN FIRST LANGUAGE INFLUENCES EXPRESSION OF OBJECT PLACEMENT EVENTS IN SECOND LANGUAGE
Authors: Lewandowski Wojciech , Özçalışkan Şeyda
Published: March 2021

Speakers show cross-linguistic differences in expressing placement events involving support (cup on table) and containment (apple in bowl) in first language (L1) contexts. They rely on either more-general (e.g., Spanish for support, Polish for containment) or more-specific (e.g., German, Polish for support; Spanish, German for containment) descriptions. Relatively less is known about the expression of placement events in second language (L2) production contexts. In this study, we examined object-placement event descriptions produced by two groups of L1 Polish speakers—with either German or Spanish as their L2—in comparison to monolingual speakers of German, Spanish, and Polish, using an animated event description task. Bilingual speakers showed greater effect of L1 patterns in moving from a more-general to a more-specific system and L2 patterns in moving from a more-specific to a more-general or between two more-specific systems, suggesting that the specificity of event expression in L1 influences patterns of placement expression in L2.
Spectrum of clinical presentation of COVID-19 in paediatric patients with cardiomyopathy and heart failure
Authors: Mantell Benjamin S. , Lytrivi Irene D. , Lee Teresa M.
Published: March 2021

As the United States’ original epicenter of the COVID-19 pandemic and one of the leading national paediatric heart failure/cardiomyopathy programs, we describe our experience with the spectrum of COVID-19 in the paediatric heart failure population.
Conscription and the Color Line: Rawls, Race and Vietnam
Authors: Terry Brandon M.
Published: March 2021

This article revisits one of John Rawls's rare forays into activist politics, his proposal presented to the Harvard faculty, calling for a denunciation of the “2-S” system of student deferments from conscription. In little-studied archival papers, Rawls argued that the draft both exposed “background” structural racial injustice and constituted a burdening of black Americans that violated the norms of fair cooperation. Rather than obscuring racial injustice and focusing exclusively on economic inequality, as Charles Mills has claimed, Rawls rejected the ascendant conservative views that naturalized black poverty or else attributed it to cultural pathologies in black families. Thus Rawls found nothing illicit in taking the position of a disadvantaged racial group as a relevant comparison when applying his ideal theory to nonideal circumstances. However, I contend in this article that Rawls's account of political philosophy as an attempt to find a consensus may be similarly ideological, leading him to displace the reality of conflict through begging descriptions, expressivist formulations, and historical romanticism.
“A Quite Similar Enterprise … Interpreted Quite Differently”? James Buchanan, John Rawls and the Politics of the Social Contract
Authors: Jackson Ben , Stemplowska Zofia
Published: March 2021

A striking aspect of the initial reception of John Rawls is that he was embraced by leading market-liberal theorists such as Friedrich Hayek and James Buchanan. This article investigates the reasons for the free-market right's sympathetic interest in the early Rawls by providing a historical account of the dialogue between Rawls and his key neoliberal interlocutor, James Buchanan. We set out the common intellectual context, notably the influence of Frank Knight, that framed the initial work of both Buchanan and Rawls and brought them together as seeming allies during the early 1960s. We then analyze a significant theoretical divergence between the two in the 1970s related to their contrasting responses to the politics of those years and to differences over the importance of ideal theory in political thought. The exchanges between Buchanan and Rawls demonstrate that Rawlsian liberalism and neoliberalism initially emerged as entwined critiques of mid-twentieth-century political economy but could not sustain that alliance when faced by the new claims for civil and social rights that became a marked feature of politics after the 1960s.
Cities and COVID-19: navigating the new normal
Authors: Khan Iman , Iftikhar Muhammad Naveed , Ali Saleem H. , Khalid Shua
Published: March 2021

Non-technical summary

Urban density is erroneously regarded as the main factor in the spread of COVID-19 in cities. A review of extant literature and findings from our case study of Karachi, Pakistan indicate that inequalities in income, healthcare, and living conditions play a key role in the spread of contagions along with government responsiveness to the pandemic. Moving forward, urban policies need to address these inequalities through changes in housing policies and decentralized governance systems. Cities must adapt to sustainable modes of travel, reduce digital inequalities, and encourage people friendly urban planning to become resilient in the face of pandemics.

Technical summary

COVID-19 has changed how urban residents relate to their cities. Urban centers have become epicenters of disease, which has raised questions about the long-term sustainability of high-density settlements and public transport usage. However, the spread of COVID-19 in cities is incorrectly attributed to urban density.

Using the case study of Karachi, Pakistan, we find that inequality of income, healthcare, and living conditions is a major contributing factor to the spread of COVID-19. Data on positive COVID-19 cases, density, and socioeconomic status were obtained at the Union Council level from administrative districts of Karachi, Pakistan between March 2020, and July 2020. Despite low population densities, low-to-middle income neighborhoods in Karachi had a higher proportion of positive cases. Further, the experience of dense cities such as Hanoi in Vietnam and New York in the US differs regarding the spread of COVID-19. Hence, the government's response to the pandemic is also a major factor in containing the outbreak.

Our findings suggest that a crisis in a city is exacerbated by its inability to take advantage of its density, inequality in the distribution of resources, lack of inclusiveness, and centralized governance mechanisms that make it difficult to respond quickly to situations. Thus, urban planning scholarship and practice should take an interdisciplinary approach to make cities equitable, inclusive, and adaptive.

Social media summary

Cities in the developing world have an opportunity for more resilient renewal in the post-COVID world.
Optimizing Precipitation Forecasts for Hydrological Catchments in Ethiopia Using Statistical Bias Correction and Multi‐Modeling
Authors: Stellingwerf Sippora , Riddle Emily , Hopson Thomas M. , Knievel Jason C. , Brown Barbara , Gebremichael Mekonnen
Published: March 2021

Accurate rainfall forecasts on timescales ranging from a few hours to several weeks are needed for many hydrological applications. This study examines bias, skill and reliability of four ensemble forecast systems (from Canada, UK, Europe, and the United States) and a multi‐model ensemble as applied to Ethiopian catchments. By verifying these forecasts on hydrological catchments, we focus on spatial scales that are relevant to many actual water forecasting applications, such as flood forecasting and reservoir optimization. By most verification metrics tested, the bias corrected European model is the best individual model at predicting daily rainfall variations, while the Canadian model shows the most realistic ensemble spread and thus the most reliable forecast probabilities, including those of extreme events. The skill of the multi‐model ensemble outperforms individual models by most metrics, and is skillful up to 9 days ahead. Skill is higher for the 0–5 day model accumulation than for the first 24 h, suggesting that timing errors strongly penalize the skill of forecasts with shorter accumulation periods. Due to seasonality in the model biases, bias correction is best applied to each month individually. Forecasting extreme rainfall is a challenge for Ethiopia, especially over mountainous regions where positive skill is only reached after bias correction. Compared to individual models, the multi‐model ensemble has a higher probability of detecting extreme rainfall and a lower false alarm rate, with usable skill at 24 h lead times.
Constraints on the Depth, Thickness, and Strength of the G Discontinuity in the Central Pacific From S Receiver Functions
Authors: Mark H. F. , Collins J. A. , Lizarralde D. , Hirth G. , Gaherty J. B. , Evans R. L. , Behn M. D.
Published: March 2021

The relative motion of the lithosphere with respect to the asthenosphere implies the existence of a boundary zone that accommodates shear between the rigid plates and flowing mantle. This shear zone is typically referred to as the lithosphere‐asthenosphere boundary (LAB). The width of this zone and the mechanisms accommodating shear across it have important implications for coupling between mantle convection and surface plate motion. Seismic observations have provided evidence for several physical mechanisms that might help enable relative plate motion, but how these mechanisms each contribute to the overall accommodation of shear remains unclear. Here we present receiver function constraints on the discontinuity structure of the oceanic upper mantle at the NoMelt site in the central Pacific, where local constraints on shear velocity, anisotropy, conductivity, and attenuation down to ∼300 km depth provide a comprehensive picture of upper mantle structure. We image a seismic discontinuity with a Vsv decrease of 4.5% or more over a 0–20 km thick gradient layer centered at a depth of ∼65 km. We associate this feature with the Gutenberg discontinuity (G), and interpret our observation of G as resulting from strain localization across a dehydration boundary based on the good agreement between the discontinuity depth and that of the dry solidus. Transitions in Vsv, azimuthal anisotropy, conductivity, and attenuation observed at roughly similar depths suggest that the G discontinuity represents a region of localized strain within a broader zone accommodating shear between the lithosphere and asthenosphere.
Adapting to Changing Labor Productivity as a Result of Intensified Heat Stress in a Changing Climate
Authors: Zhu Jinxin , Wang Shuo , Zhang Boen , Wang Dagang
Published: March 2021

The intensification of heat stress reduces the labor capacity and hence poses a threat to socio‐economic development. The reliable projection of the changing climate and the development of sound adaptation strategies are thus desired for adapting to the decreasing labor productivity under climate change. In this study, an optimization modeling approach coupled with dynamical downscaling is proposed to design the optimal adaptation strategies for improving labor productivity under heat stress in China. The future changes in heat stress represented by the wet‐bulb globe temperature (WBGT) are projected with a spatial resolution of 25 × 25 km by a regional climate model (RCM) through the dynamical downscaling of its driving global climate model (GCM). Uncertain information such as system costs, environmental costs, and subsidies are also incorporated into the optimization process to provide reliable decision alternatives for improving labor productivity. Results indicate that the intensification of WBGT is overestimated by the GCM compared to the RCM. Such an overestimation can lead to more losses in working hours derived from the GCM than those from the RCM regardless of climate scenarios. Nevertheless, the overestimated heat stress does not alter the regional measures taken to adapt to decreasing labor productivity. Compared to inland regions, the monsoon‐affected regions tend to improve labor productivity by applying air conditioning rather than working overtime due to the cost differences. Consequently, decision‐makers need to optimally make a balance between working overtime and air conditioning measures to meet sustainable development goals.
Autocorrelation of the Ground Vibrations Recorded by the SEIS‐InSight Seismometer on Mars
Authors: Compaire N. , Margerin L. , Garcia R. F. , Pinot B. , Calvet M. , Orhand‐Mainsant G. , Kim D. , Lekic V. , Tauzin B. , Schimmel M. , Stutzmann E. , Knapmeyer‐Endrun B. , Lognonné P. , Pike W. T. , Schmerr N. , Gizon L. , Banerdt W. B.
Published: March 2021

Since early February 2019, the SEIS (Seismic Experiment for Interior Structure) seismometer deployed at the surface of Mars in the framework of the InSight mission has been continuously recording the ground motion at Elysium Planitia. In this study, we take advantage of this exceptional data set to put constraints on the crustal properties of Mars using seismic interferometry (SI). To carry out this task, we first examine the continuous records from the very broadband seismometer. Several deterministic sources of environmental noise are identified and specific preprocessing strategies are presented to mitigate their influence. Applying the principles of SI to the single‐station configuration of InSight, we compute, for each Sol and each hour of the martian day, the diagonal elements of the time‐domain correlation tensor of random ambient vibrations recorded by SEIS. A similar computation is performed on the diffuse waveforms generated by more than a hundred Marsquakes. A careful signal‐to‐noise ratio analysis and an inter‐comparison between the two datasets suggest that the results from SI are most reliable in a narrow frequency band around 2.4 Hz, where an amplification of both ambient vibrations and seismic events is observed. The average autocorrelation functions (ACFs) contain well identifiable seismic arrivals, that are very consistent between the two datasets. Interpreting the vertical and horizontal ACFs as, respectively, the P‐ and S‐ seismic reflectivity below InSight, we propose a simple stratified velocity model of the crust, which is mostly compatible with previous results from receiver function analysis. Our results are discussed and compared to recent works from the literature.
Time-expanded phase-sensitive optical time-domain reflectometry
Authors: Soriano-Amat Miguel , Martins Hugo F. , Durán Vicente , Costa Luis , Martin-Lopez Sonia , Gonzalez-Herraez Miguel , Fernández-Ruiz María R.
Published: March 2021

Phase-sensitive optical time-domain reflectometry (ΦOTDR) is a well-established technique that provides spatio-temporal measurements of an environmental variable in real time. This unique capability is being leveraged in an ever-increasing number of applications, from energy transportation or civil security to seismology. To date, a wide number of different approaches have been implemented, providing a plethora of options in terms of performance (resolution, acquisition bandwidth, sensitivity or range). However, to achieve high spatial resolutions, detection bandwidths in the GHz range are typically required, substantially increasing the system cost and complexity. Here, we present a novel ΦOTDR approach that allows a customized time expansion of the received optical traces. Hence, the presented technique reaches cm-scale spatial resolutions over 1 km while requiring a remarkably low detection bandwidth in the MHz regime. This approach relies on the use of dual-comb spectrometry to interrogate the fibre and sample the backscattered light. Random phase-spectral coding is applied to the employed combs to maximize the signal-to-noise ratio of the sensing scheme. A comparison of the proposed method with alternative approaches aimed at similar operation features is provided, along with a thorough analysis of the new trade-offs. Our results demonstrate a radically novel high-resolution ΦOTDR scheme, which could promote new applications in metrology, borehole monitoring or aerospace.
Correction to: Current and future applications of induced pluripotent stem cell-based models to study pathological proteins in neurodegenerative disorders
Authors: de Rus Jacquet Aurélie , Denis Hélèna L. , Cicchetti Francesca , Alpaugh Melanie
Published: March 2021

A Correction to this paper has been published: https://doi.org/10.1038/s41380-021-01055-8
Orphan nuclear receptors as regulators of intratumoral androgen biosynthesis in castration-resistant prostate cancer
Authors: Zhou Jianfu , Wang Yuliang , Wu Dinglan , Wang Shusheng , Chen Zhiqiang , Xiang Songtao , Chan Franky Leung
Published: March 2021

Castration-resistant prostate cancer (CRPC) almost invariably occurs after androgen-deprivation therapy (ADT) for the advanced metastatic disease. It is generally believed that among multiple mechanisms and signaling pathways, CRPC is significantly driven by the reactivation of androgen receptor (AR) signaling in ADT-treated patients with castrate levels of androgen, partially at least mediated by the androgen biosynthesis within the tumor, also known as intratumoral or intraprostatic androgen biosynthesis. Steroidogenic enzymes, such as CYP11A1, CYP17A1, HSD3B1, AKR1C3 and SRD5A, are essential to catalyze the conversion of the initial substrate cholesterol into potent androgens that confers the CRPC progression. Accumulating evidences indicate that many steroidogenic enzymes are upregulated in the progression setting; however, little is known about the dysregulation of these enzymes in CRPC. Orphan nuclear receptors (ONRs) are members of the nuclear receptor superfamily, of which endogenous physiological ligands are unknown and which are constitutively active independent of any physiological ligands. Studies have validated that besides AR, ONRs could be the potential therapeutic targets for prostate cancer, particularly the lethal CRPC progression. Early studies reveal that ONRs play crucial roles in the transcriptional regulation of steroidogenic enzyme genes. Notably, we and others show that three distinct ONRs, including liver receptor homolog-1 (LRH-1, NR5A2), steroidogenic factor 1 (SF-1, AD4BP, NR5A1) and estrogen-related receptor α (ERRα, NR3B1), can contribute to the CRPC progression by promotion of the intratumoral androgen synthesis via their direct transcriptional regulation on multiple steroidogenic enzymes. This review presents an overview of the current understanding on the intratumoral androgen biosynthesis in CRPC, with a special focus on the emerging roles of ONRs in this process.
A self-organized synthetic morphogenic liposome responds with shape changes to local light cues
Authors: Gavriljuk Konstantin , Scocozza Bruno , Ghasemalizadeh Farid , Seidel Hans , Nandan Akhilesh P. , Campos-Medina Manuel , Schmick Malte , Koseska Aneta , Bastiaens Philippe I. H.
Published: March 2021

Reconstituting artificial proto-cells capable of transducing extracellular signals into cytoskeletal changes can reveal fundamental principles of how non-equilibrium phenomena in cellular signal transduction affect morphogenesis. Here, we generated a Synthetic Morphogenic Membrane System (SynMMS) by encapsulating a dynamic microtubule (MT) aster and a light-inducible signaling system driven by GTP/ATP chemical potential into cell-sized liposomes. Responding to light cues in analogy to morphogens, this biomimetic design embodies basic principles of localized Rho-GTPase signal transduction that generate an intracellular MT-regulator signaling gradient. Light-induced signaling promotes membrane-deforming growth of MT-filaments by dynamically elevating the membrane-proximal tubulin concentration. The resulting membrane deformations enable recursive coupling of the MT-aster with the signaling system, which generates global self-organized morphologies that reorganize towards local external cues in dependence on prior shape. SynMMS thereby signifies a step towards bio-inspired engineering of self-organized cellular morphogenesis.
Graded recruitment of pupil-linked neuromodulation by parametric stimulation of the vagus nerve
Authors: Mridha Zakir , de Gee Jan Willem , Shi Yanchen , Alkashgari Rayan , Williams Justin , Suminski Aaron , Ward Matthew P. , Zhang Wenhao , McGinley Matthew James
Published: March 2021

Vagus nerve stimulation (VNS) is thought to affect neural activity by recruiting brain-wide release of neuromodulators. VNS is used in treatment-resistant epilepsy, and is increasingly being explored for other disorders, such as depression, and as a cognitive enhancer. However, the promise of VNS is only partially fulfilled due to a lack of mechanistic understanding of the transfer function between stimulation parameters and neuromodulatory response, together with a lack of biosensors for assaying stimulation efficacy in real time. We here develop an approach to VNS in head-fixed mice on a treadmill and show that pupil dilation is a reliable and convenient biosensor for VNS-evoked cortical neuromodulation. In an ‘optimal’ zone of stimulation parameters, current leakage and off-target effects are minimized and the extent of pupil dilation tracks VNS-evoked basal-forebrain cholinergic axon activity in neocortex. Thus, pupil dilation is a sensitive readout of the moment-by-moment, titratable effects of VNS on brain state.
The impact of contact tracing and household bubbles on deconfinement strategies for COVID-19
Authors: Willem Lander , Abrams Steven , Libin Pieter J. K. , Coletti Pietro , Kuylen Elise , Petrof Oana , Møgelmose Signe , Wambua James , Herzog Sereina A. , Faes Christel , Beutels Philippe , Hens Niel
Published: March 2021

The COVID-19 pandemic caused many governments to impose policies restricting social interactions. A controlled and persistent release of lockdown measures covers many potential strategies and is subject to extensive scenario analyses. Here, we use an individual-based model (STRIDE) to simulate interactions between 11 million inhabitants of Belgium at different levels including extended household settings, i.e., “household bubbles”. The burden of COVID-19 is impacted by both the intensity and frequency of physical contacts, and therefore, household bubbles have the potential to reduce hospital admissions by 90%. In addition, we find that it is crucial to complete contact tracing 4 days after symptom onset. Assumptions on the susceptibility of children affect the impact of school reopening, though we find that business and leisure-related social mixing patterns have more impact on COVID-19 associated disease burden. An optimal deployment of the mitigation policies under study require timely compliance to physical distancing, testing and self-isolation.