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How Computational Complexity Can Restore General Equilibrium in Markets with Indivisible Goods
No full textWe study market equilibrium in settings with indivisible goods and tight budget constraints, where a traditional Walrasian Equilibrium (WE) may fail to exist. We introduce the Complexity Compensating Equilibrium (CCE), in which prices endogenously render the budget problem computationally difficult. Complexity induces heterogeneous demands even among agents with homogeneous preferences, as individuals allocate varying levels of cognitive effort. We define the equilibrium region as the set of price configurations that satisfy the necessary economic and computational conditions for equilibrium to exist. In this region, price configurations maximize the difficulty of the budget problem in addition to satisfying market clearing conditions. We evaluate the predictions of CCE through a controlled market experiment. We find that trading prices consistently force the budget problem to the equilibrium region. Further supporting and central to the CCE framework, the equilibrium bundles of goods generate markedly different utility levels across agents. This outcome contradicts a core feature of WE, namely, the equalization of utilities. In a setting where it exists, we reject WE on both prices and utilities, in favour of CCE
Electrical impedance tomography revisited
No full textWe revisit the inverse problem associated with Electrical Impedance Tomography. This important imaging technique has numerous clinical applications, in particular in pulmonary, cardiac and brain imaging, as well as in the detection of breast cancer. We simplify the derivations of the basic analytical inversion formula. Also, we introduce a novel computational inversion algorithm, which by harvesting powerful analytical and geometrical techniques, yields a drastically faster algorithm than the one arising from the current d-bar approach. The approximate time to reconstruct a typical phantom is reduced from 15 min to 5 s
The origins of dengue and chikungunya viruses in Ecuador following increased migration from Venezuela and Colombia.
No full textBACKGROUND: In recent years, Ecuador and other South American countries have experienced an increase in arboviral diseases. A rise in dengue infections was followed by introductions of chikungunya and Zika, two viruses never before seen in many of these areas. Furthermore, the latest socioeconomic and political instability in Venezuela and the mass migration of its population into the neighboring countries has given rise to concerns of infectious disease spillover and escalation of arboviral spread in the region. RESULTS: We performed phylogeographic analyses of dengue (DENV) and chikungunya (CHIKV) virus genomes sampled from a surveillance site in Ecuador in 2014-2015, along with genomes from the surrounding countries. Our results revealed at least two introductions of DENV, in 2011 and late 2013, that initially originated from Venezuela and/or Colombia. The introductions were subsequent to increases in the influx of Venezuelan and Colombian citizens into Ecuador, which in 2013 were 343% and 214% higher than in 2009, respectively. However, we show that Venezuela has historically been an important source of DENV dispersal in this region, even before the massive exodus of its population, suggesting already established paths of viral distribution. Like DENV, CHIKV was introduced into Ecuador at multiple time points in 2013-2014, but unlike DENV, these introductions were associated with the Caribbean. Our findings indicated no direct CHIKV connection between Ecuador, Colombia, and Venezuela as of 2015, suggesting that CHIKV was, at this point, not following the paths of DENV spread. CONCLUSION: Our results reveal that Ecuador is vulnerable to arbovirus import from many geographic locations, emphasizing the need of continued surveillance and more diversified prevention strategies. Importantly, increase in human movement along established paths of viral dissemination, combined with regional outbreaks and epidemics, may facilitate viral spread and lead to novel virus introductions. Thus, strengthening infectious disease surveillance and control along migration routes and improving access to healthcare for the vulnerable populations is of utmost importance
Quantum estimation of cosmological parameters
No full textUnderstanding how well future cosmological experiments can reconstruct the mechanism that generated primordial inhomogeneities is key to assessing the extent to which cosmology can inform fundamental physics. In this work, we apply a quantum metrology tool — the quantum Fisher information — to the squeezed quantum state describing cosmological perturbations at the end of inflation. This quantifies the ultimate precision achievable in parameter estimation, assuming ideal access to early-universe information. By comparing the quantum Fisher information to its classical counterpart — derived from measurements of the curvature perturbation power spectrum alone (homodyne measurement) — we evaluate how close current observations come to this quantum limit. Focusing on the tensor-to-scalar ratio as a case study, we find that the gap between classical and quantum Fisher information grows exponentially with the number of e-folds a mode spends outside the horizon. This suggests the existence of a highly efficient (but presently inaccessible) optimal measurement. Conversely, we show that accessing the decaying mode of inflationary perturbations is a necessary (but not sufficient) condition for exponentially improving the inference of the tensor-to-scalar ratio
Pathogen genomics in healthcare: overcoming barriers to proactive surveillance
No full textPathogen genomic surveillance in healthcare has the potential to enhance patient safety by detecting outbreaks earlier, thereby reducing morbidity and mortality. Despite benefits, there are barriers to adoption, including cost, expertise, and lack of standardized methodologies and incentives. This commentary advocates for 1) investment from healthcare payors, public health, and regulatory bodies and 2) additional research on genomic surveillance for improving patient outcomes and reducing infections. Effective implementation will require strategic investment and cross-sector collaboration
Children as Witnesses: Remembering, Reporting, and Reliability
No full textChildren's ability to provide detailed and accurate testimony about their experiences has been of interest to developmental and applied cognitive scientists for several decades. In this review, we consider how the contributions of both the child and the interviewer must be considered in tandem when evaluating the reliability of the child's testimony. We consider important aspects of children's cognitive and social development that underpin their contributions in forensic interviews as well as interviewer behavior that might enhance or undermine the quality of children's testimony. We outline important emerging (and continuing) issues for researchers working in this area. Researchers around the globe recognize that young people can be reliable witnesses although, as with adults, their ability to do so is influenced by the convergence of a number of different factors, the most important of which are the ways in which they are questioned about their experiences
Jill Jäger MCH (Making Climate History) Oral History Interview
No full textOral history interview with Jill Jäger conducted by Sarah Dry on 15th and 16th November, 2021 as part of the Making Climate History project.
Time-Stamped Summary
Track One
Early life in Sale [I: 00:58]
Final years of schooling and choosing a university [I: 07:09]
Appeal of University of East Anglia and ‘Environmental Sciences’ [I: 12:06]
Experience at UEA [I:13:18]
Appeal of interdisciplinarity in geography and in ES at UEA [I:18:01]
Experience at UEA continued [I: 19:39]
Deciding on PhD programs in the States [I: ~25:00:00]
Early computer work at UEA [I: 30:54]
Memories of arriving in Boulder for PhD [I: 32:41]
Phd topic on modeling the ice age climate and joint initiative with NCAR [I: ~37:00:00]
Memories of early climate models [I: 40:00]
Field trips in Boulder, CO [I: 46:37]
Recollections of Ed Lorenz [I: 53:58]
Idea of the ’System’ (of systems-thinking): [I: 1:02:53]
Recollections of PhD defense, completing her doctorate at 24 [I: 1:03:38]
Work on temperature, pressure, and precipitation trends with Harry Van Loon [I: 1:12:29]
Evidence of Arctic warming [I: 1:16:23]
Track Two
Relationship between models and empirical data [II: 05:01]
Return to the UK (Norwich) and time at CRU: [II: 07:51]
Being hired by Wolf Hafele at IIASA [The International Institute for Applied Systems Analysis] [II: ~08;00]
Culture shock of returning (albeit briefly) to CRU [II: 16:53]
Learning curve of IIASA and early experiences there [II: 23:31]
Climate modelling and systems analysis, limits thereof [II: 33:01]
Nuclear power [II: 39:17]
Meeting Fredy Jäger, her husband [II: 40:36]
Studies, and critiques of, energy systems [II: 46:25]
Recollections of Dennis and Dana Meadows [II: 54:38]
‘Man’s world’ of IIASA and science more broadly [II: 58:07]
Return to NCAR post-IIASA [II: 1:03:27]
1978 workshop on ‘Carbon Dioxide, Climate and Society’ [II: 1:04:58]
1979 World Climate Conference [II: 1:17:23]
Track Three
Decision to work as a consultant, first child born [III: 02:04]
Work on preparing the 1985 Villach Conference [III11:35]
Important change between focusing on CO2 and including other greenhouse gases in projections [III: 18:17]
Recollections of Villach Conference [III: 20:39]
Work with advisory group on greenhouse gases with Beijer Institute in Stockholm [III: 28:23]
Inclusion of ‘decision-makers’ in subsequent meetings on climate change [III: 33:29]
Recollections of the World Conference on the Changing Atmosphere: Implications for Global Security in Toronto, 1988 [III: 39:20]
Political pressure by the US, post Villach and Bellagio, to have more government-led focus on climate change resulting in IPCC [III: 48:00]
Recollections of Bert Bolin [III: 53:30]
Recollections of Second World Climate Conference 1990, shift towards including ministerial and political actors [III: 58:15]
Importance of clear and synthetic writing (Jäger’s) under pressure at all of these conferences [III: 1:03:31]
Track Four
Balancing work and family [IV: 00:09]
Role and work at the Wuppertal Institute for Climate, Environment and Energy [IV: 12:13]
Returning to IIASA as Deputy Director [IV: 12:59]
Role of modeling at IIASA [IV: 36:02]
Defining ‘dangerous’ in relation to climate change [IV: 40:13]
Relationship between IIASA and IPCC [IV: 43:06]
Feelings about the future in relation to actions on climate change [IV: 52:21]
Human Dimensions Programme [IV: 55:19]
Emergence of the idea of ‘integrated assessment’ [IV: 1:08:12]
Emergence and evolution of idea of ‘sustainability science’ [IV: 1:10:45]
MATISSE project, CLIMSAVE project and power of scenarios [IV: 1:16:22]
Distinctions between ‘problem-oriented’ and ’solutions-oriented’ work [IV: 1:25:43]
Passion for the value and utility of scenarios [IV: 1:32:07
Mechanisms Underlying Mesenchymal Stem Cell-Derived Extracellular Vesicle Modulation of Sensory Neuron Excitability
No full textMesenchymal stem cells (MSCs) represent a promising therapeutic approach for a range of conditions, including osteoarthritis (OA). Increasing evidence highlights the critical role of MSC-derived extracellular vesicles (EVs), which facilitate the transfer of biomolecular cargo between cells. Our previous work demonstrated that MSC-EVs alleviate pain in a murine model of OA by reducing OA-induced sensory neuron hyperexcitability, rather than altering joint pathology. These findings underscore the therapeutic potential of MSC-EVs in pain management. We further showed that MSC-EVs can directly inhibit sensitisation of dorsal root ganglion (DRG) neurons induced by nerve growth factor (NGF), a key mediator implicated in OA pathogenesis and associated pain.
The present study sought to elucidate the mechanisms by which MSC-EVs prevent NGF-induced sensitisation of DRG neurons, using whole-cell patch-clamp electrophysiology. Surface proteins were first removed from MSC-EVs through proteolytic “shaving,” revealing that shaved EVs were unable to fully reproduce the effects observed with intact EVs. We then established that chronic (48-hour), but not acute (10-minute), exposure to MSC-EVs was necessary to prevent NGF-induced sensitisation. These findings suggest that EV internalisation is at least partially required and that transcriptional changes may underlie the observed effects. Consistent with this hypothesis, inhibition of transcription with actinomycin D attenuated the full protective effect of MSC-EVs.
A review of the literature identified several intracellular biomolecules potentially responsible for these effects, including microRNAs (miRNAs), many of which are known to modulate pain pathways. Accordingly, small RNA sequencing was performed to characterise the miRNA cargo of MSC-EVs. Candidate miRNAs with established roles in pain were subsequently selected and assessed for their capacity to modulate NGF-induced sensitisation of DRG neurons.
In addition to the central focus of this thesis, complementary studies examined the influence of OA-associated mediators on neuronal excitability. One investigation demonstrated that the sphingomyelin species N-palmitoyl-D-erythro-sphingosylphosphorylcholine (d18:1/16:0), elevated in OA synovial fluid, sensitises DRG neurons and induces inflammatory joint pain in mice. A further study revealed that the neurotrophic factor artemin sensitises sensory neurons in both OA-susceptible mice and OA-resistant naked mole-rats, although additional in vivo studies are required to determine whether these in vitro findings translate into behavioural changes.
In summary, this thesis advances understanding of the mechanisms by which MSC-EVs regulate neuronal excitability and clarifies how specific OA-associated mediators contribute to sensory neuron sensitisation
Longitudinal Trends in Pediatric Non-Salmonella Gram-negative Enterobacterales Infections at a Tertiary Care Center in West Africa, 2005-2023.
No full textBACKGROUND: Despite data demonstrating the high prevalence of third-generation cephalosporin resistant gram-negative Enterobacterales (GNE) among children in sub-Saharan Africa, longitudinal descriptions of resistance among these pathogens from Francophone West Africa remain rare. METHODS: We conducted a retrospective analysis of pathogen-positive children 0-15 years old included in an invasive bacterial infection study at l'Hôpital Gabriel Touré (in Bamako, Mali) from 2005-2023. We aimed to describe changes in pathogen burden and non-Salmonella GNE resistance over time and compare in-hospital mortality between patients with and without non-Salmonella GNE pathogens. Isolates from 2021-2023 underwent whole genome sequencing to identify genes conferring antimicrobial resistance. RESULTS: Of 3,803 pathogen-positive patients, 392 grew at least one non-Salmonella GNE pathogen. The proportion of pathogen-positive patients with non-Salmonella GNE increased (6% vs. 38%) from 2005-2023. Third-generation cephalosporin and multidrug resistance among non-Salmonella GNE increased from 30% and 55%, respectively, in 2005-2009, to 93% (both) by 2021-2023. Children 0-2 months old from outside Bamako and 3 months-15 years old from and from outside Bamako with non-Salmonella GNE had higher mortality odds (3.17, 95% CI 1.69-5.95; 2.13, 95% CI 1.44-3.14; and 2.25, 95% CI 1.38-3.66, respectively) than similar patients with other pathogens. Sequencing confirmed the presence of the emerging pathogen Pantoea dispersa and revealed genes conferring multidrug resistance. CONCLUSIONS: Data from this large pediatric referral center in Mali show a high and rising burden of multidrug-resistant gram-negative Enterobacterales. These patterns reflect concerns increasingly reported across sub-Saharan Africa, highlighting the urgency of strengthening antimicrobial access, diagnostics, and stewardship strategies in similar settings
A Crisis Without Replication: Replication, the Current Crisis in Psychology, and Open Science Investigated Using Insights From Metascience
No full textPsychology and related fields have been gripped by the replication crisis since at least 2011. In response to this problem, a new field of empirical metascience has emerged, focusing on finding causes and solutions. This development opens a mutually beneficial pathway: philosophy of science can be informed by metascientific results, and metascience can take rigorous insights from philosophy of science as a theoretical basis. Throughout this dissertation, I draw specifically on metascientific evidence as a methodological choice to inform conceptual analyses of key concepts surrounding the replication crisis.
In the first chapter, I introduce the replication crisis and the motivation for this dissertation. In the second chapter, I consider the concept of replication and possible accounts of it, argue that the concept is redundant and propose a deflationary account instead. In chapters three to five, I examine the aetiology of the crisis. Chapter three reframes the replication crisis as a crisis of inference, which I show is a better explanation of our surprise at replication failures. This account also enables an integration of the plethora of proposed crises under the umbrella of ill-adjusted inference. The fourth chapter explores the green thumb explanation of individual replication failures and finds it at best unconvincing or even deeply worrying for psychology as a field of research. Chapter five considers the concept of questionable research practices (QRPs), arguing for the elimination of the label. Instead of focusing on QRPs, I argue that we should question research practice and understand instances of practices currently described as QRPs on a context-dependent spectrum from good to bad. Finally, in chapter six I examine the main proposed solutions: open science practices. I explain that these practices can help solve the crisis if we assume a hostile epistemic environment at the core of the problem, but not if we assume widespread epistemic vice. A combination of more appropriate inferences, clearer conceptual thinking, and better as well as more open research practices may help psychology leave its crisis behind while securing its future