Matrix inequalities with applications to the theory of iterated kernels

NOTICE: this is the author's version of a work that was accepted for publication in Linear Algebra and its Applications. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Linear Algebra and its Applications, Volume 362 (2003), pp.275-286. doi:10.1016/S0024-3795(02)00517-7. http://www.elsevier.com/locate/laa.For an m × n matrix A with nonnegative real entries, Atkinson, Moran and Watterson proved the inequality s(A)3 ≤ mns(AAtA), where At is the transpose of A, and s(·) is the sum of the entries. We extend this result to finite products of the form AAtAAt . . .A or AAtAAt . . .At and give some applications to the theory of iterated kernels

Dualities of Latin America

Determining whether the current situation of Latin America is better described as "post-neoliberalism" or as "commodities consensus" requires an analysis of recent changes in the region. Capitalism has expanded in agriculture and mining, accentuating the preeminence of basic exports. Traditional industry is declining, and remittances and tourism have increased in importance. Local capitalists associated with foreign corporations have replaced the national bourgeoisie, while the exodus of peasants consolidates labor precariousness, poverty, and inequality. At the same time, the United States is deploying troops to reorganize its domination. The South American rebellions have limited neoliberal aggression and achieved unusual victories in other parts of the world. The concept of post-neoliberalism emphasizes the region's political turn toward autonomy but overlooks the persistence of the economic model generated during the previous phase. The opposing concept, commodities consensus, highlights the extractivism prevailing throughout the region but plays down the extreme divergences among right-wing, center-left, and radical governments in all other areas. Both concepts contain part of the truth, but neither fully explains the regional scenario.Para determinar si la situación actual de Latinoamérica es mejor descrita como “postneoliberalismo” o como un “consenso de los commodities” hay que hacer un análisis de los cambios recientes en la región. El capitalismo se ha expandido en la agricultura y la minería, acrecentando la preeminencia de las exportaciones básicas. La industria tradicional ha disminuido, y la importancia del turismo y las remesas ha aumentado. Los capitalistas locales asociados con empresas extranjeras han reemplazado a la burguesía nacional, mientras que el éxodo de los campesinos ha consolidado la precariedad laboral, la pobreza y la desigualdad. Al mismo tiempo, Estados Unidos despliega tropas para reorganizar su dominio. Las rebeliones en América del Sur han puesto barreras a la agresión neoliberal y logrado victorias inusuales en otras partes del mundo. El concepto del postneoliberalismo destaca el giro político de la región hacia la autonomía pero con una tendencia a la persistencia del modelo económico generado durante la fase anterior. El otro concepto, el consenso de las commodities, destaca el extractivismo que prevalece en toda la región pero minoriza las divergencias entre los gobiernos de derecha, centro-izquierda y radicales en todas las demás áreas. Ambos conceptos son parcialmente ciertos, pero no explican totalmente el escenario regional.Fil: Katz, Claudio Isaac. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Improvements in health-related quality of life with belimumab, a B-lymphocyte stimulator-specific inhibitor, in patients with autoantibody-positive systemic lupus erythematosus from the randomised controlled BLISS trials

OBJECTIVE: Assess the effects of belimumab treatment plus standard systemic lupus erythematosus (SLE) therapy on health-related quality of life (HRQOL) in patients with active, autoantibody-positive SLE. METHODS: Patients received standard therapy plus placebo or belimumab 1 or 10 mg/kg in two multicentre, randomised controlled trials of 52 (BLISS-52; N=865) and 76 (BLISS-76; N=819) weeks' duration. Responders were evaluated by SLE Responder Index at week 52. Patient-reported outcome assessments included SF-36, Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue, and EQ-5D. RESULTS: Mean SF-36 Physical Component Summary (PCS) scores at week 24 was a major secondary endpoint. Baseline SF-36 scores were 1.5 SDs below age-/sex-matched US norms with similar improvement at week 24 across treatment groups. Mean changes from baseline in PCS scores were significantly (p<0.05) greater with belimumab 1 mg/kg (4.20) and 10 mg/kg (4.18) versus placebo (2.96) in BLISS-52, week 52. In BLISS-76, significantly (p<0.05) greater improvements were seen with belimumab 1 mg/kg in PCS (belimumab 1 mg/kg=4.37, 10 mg/kg=3.41 vs placebo=2.85) and Mental Component Summary (MCS) scores (belimumab 1 mg/kg=3.14, 10 mg/kg=2.70 vs placebo=1.40) at week 52, and in MCS score at week 76 (belimumab 1 mg/kg=3.05, 10 mg/kg=2.28 vs placebo=1.36). In pooled analysis, significantly greater improvements in PCS, SF-36 vitality domain, and FACIT-Fatigue scores at week 52 were evident with both belimumab doses. CONCLUSIONS: The clinically meaningful improvements in HRQOL in autoantibody-positive patients with active SLE treated with belimumab and standard therapy are consistent with the reductions in disease activity observed in these trials

Exploratory investigation of impact loads during the forward handspring vault

The purpose of this study was to examine kinematic and kinetic differences in low and high intensity hand support impact loads during a forward handspring vault. A high-speed video camera (500 Hz) and two portable force platforms (500 Hz) were installed on the surface of the vault table. Two-dimensional analyses were conducted on 24 forward handspring vaults performed by 12 senior level, junior Olympic program female gymnasts (16.9 ±1.4 yr; body height 1.60 ±0.1 m; body mass 56.7 ±7.8 kg). Load intensities at impact with the vault table were classified as low (peak force 0.8 x body weight). These vaults were compared via crucial kinetic and kinematic variables using independent t-tests and Pearson correlations. Statistically significant (p < 0.001) differences were observed in peak force (t(24) = 4.75, ES = 3.37) and time to peak force (t(24) = 2.07, ES = 1.56). Statistically significant relationships between the loading rate and time to peak force were observed for high intensity loads. Peak force, time to peak force, and a shoulder angle at impact were identified as primary variables potentially involved in the determination of large repetitive loading rates on the forward handspring vault

The ancestral retinoic acid receptor was a low-affinity sensor triggering neuronal differentiation.

Retinoic acid (RA) is an important intercellular signaling molecule in vertebrate development, with a well-established role in the regulation of hox genes during hindbrain patterning and in neurogenesis. However, the evolutionary origin of the RA signaling pathway remains elusive. To elucidate the evolution of the RA signaling system, we characterized RA metabolism and signaling in the marine annelid Platynereis dumerilii, a powerful model for evolution, development, and neurobiology. Binding assays and crystal structure analyses show that the annelid retinoic acid receptor (RAR) binds RA and activates transcription just as vertebrate RARs, yet with a different ligand-binding pocket and lower binding affinity, suggesting a permissive rather than instructive role of RA signaling. RAR knockdown and RA treatment of swimming annelid larvae further reveal that the RA signal is locally received in the medial neuroectoderm, where it controls neurogenesis and axon outgrowth, whereas the spatial colinear hox gene expression in the neuroectoderm remains unaffected. These findings suggest that one early role of the new RAR in bilaterian evolution was to control the spatially restricted onset of motor and interneuron differentiation in the developing ventral nerve cord and to indicate that the regulation of hox-controlled anterior-posterior patterning arose only at the base of the chordates, concomitant with a high-affinity RAR needed for the interpretation of a complex RA gradient

Ancient DNA evidence for the ecological globalization of cod fishing in medieval and post-medieval Europe

Understanding the historical emergence and growth of long-range fisheries can provide fundamental insights into the timing of ecological impacts and the development of coastal communities during the last millennium. Whole-genome sequencing approaches can improve such understanding by determining the origin of archaeological fish specimens that may have been obtained from historic trade or distant water. Here, we used genome-wide data to individually infer the biological source of 37 ancient Atlantic cod specimens (ca 1050-1950 CE) from England and Spain. Our findings provide novel genetic evidence that eleventh- to twelfth-century specimens from London were predominantly obtained from nearby populations, while thirteenth- to fourteenth-century specimens were derived from distant sources. Our results further suggest that Icelandic cod was indeed exported to London earlier than previously reported. Our observations confirm the chronology and geography of the trans-Atlantic cod trade from Newfoundland to Spain starting by the early sixteenth century. Our findings demonstrate the utility of whole-genome sequencing and ancient DNA approaches to describe the globalization of marine fisheries and increase our understanding regarding the extent of the North Atlantic fish trade and long-range fisheries in medieval and early modern time

Elevated A20 promotes TNF-induced and RIPK1-dependent intestinal epithelial cell death

Intestinal epithelial cell (IEC) death is a common feature of inflammatory bowel disease (IBD) that triggers inflammation by compromising barrier integrity. In many patients with IBD, epithelial damage and inflammation are TNF-dependent. Elevated TNF production in IBD is accompanied by increased expression of the TNFAIP3 gene, which encodes A20, a negative feedback regulator of NF-κB. A20 in intestinal epithelium from patients with IBD coincided with the presence of cleaved caspase-3, and A20 transgenic (Tg) mice, in which A20 is expressed from an IEC-specific promoter, were highly susceptible to TNF-induced IEC death, intestinal damage, and shock. A20-expressing intestinal organoids were also susceptible to TNF-induced death, demonstrating that enhanced TNF-induced apoptosis was a cell-autonomous property of A20. This effect was dependent on Receptor Interacting Protein Kinase 1 (RIPK1) activity, and A20 was found to associate with the Ripoptosome complex, potentiating its ability to activate caspase-8. A20-potentiated RIPK1-dependent apoptosis did not require the A20 deubiquitinase (DUB) domain and zinc finger 4 (ZnF4), which mediate NF-κB inhibition in fibroblasts, but was strictly dependent on ZnF7 and A20 dimerization. We suggest that A20 dimers bind linear ubiquitin to stabilize the Ripoptosome and potentiate its apoptosis-inducing activity

Friends or foes? migrants and sub-state nationalists in Europe

How do sub-state nationalists respond to the growing presence of cultural diversity in their ‘homelands’ resulting from migration? Sub-state nationalists in Europe, in ‘nations without states’ such as Catalonia and Scotland, have been challenging the traditional nation-state model for many decades. While the arguments in favour of autonomy or independence levelled by these movements have become more complex, sub-state nationalist movements remain grounded by their perceived national community that is distinct from the majority nation. Migration to the ‘homeland’ of a sub-state nation, then, presents a conundrum for sub-state elites that we label the ‘legitimation paradox’: too much internal diversity may undermine the claim to cultural distinctiveness. We engage with three common intervening variables thought to influence how sub-state nationalists confront the ‘legitimation paradox’: civic/ethnic nationalism, degree of political autonomy, and party competition. Our overarching argument is that none of these factors have a unidirectional or determinate effect on the sub-state nationalism-immigration nexus, which is why the nuanced case studies that comprise this Special Issue are worthwhile endeavours

Risk factors for developing ventilator-associated lower respiratory tract infection in patients with severe COVID-19:a multinational, multicentre study, prospective, observational study

Around one-third of patients diagnosed with COVID-19 develop a severe illness that requires admission to the Intensive Care Unit (ICU). In clinical practice, clinicians have learned that patients admitted to the ICU due to severe COVID-19 frequently develop ventilator-associated lower respiratory tract infections (VA-LRTI). This study aims to describe the clinical characteristics, the factors associated with VA-LRTI, and its impact on clinical outcomes in patients with severe COVID-19. This was a multicentre, observational cohort study conducted in ten countries in Latin America and Europe. We included patients with confirmed rtPCR for SARS-CoV-2 requiring ICU admission and endotracheal intubation. Only patients with a microbiological and clinical diagnosis of VA-LRTI were included. Multivariate Logistic regression analyses and Random Forest were conducted to determine the risk factors for VA-LRTI and its clinical impact in patients with severe COVID-19. In our study cohort of 3287 patients, VA-LRTI was diagnosed in 28.8% [948/3287]. The cumulative incidence of ventilator-associated pneumonia (VAP) was 18.6% [610/3287], followed by ventilator-associated tracheobronchitis (VAT) 10.3% [338/3287]. A total of 1252 bacteria species were isolated. The most frequently isolated pathogens were Pseudomonas aeruginosa (21.2% [266/1252]), followed by Klebsiella pneumoniae (19.1% [239/1252]) and Staphylococcus aureus (15.5% [194/1,252]). The factors independently associated with the development of VA-LRTI were prolonged stay under invasive mechanical ventilation, AKI during ICU stay, and the number of comorbidities. Regarding the clinical impact of VA-LRTI, patients with VAP had an increased risk of hospital mortality (OR [95% CI] of 1.81 [1.40-2.34]), while VAT was not associated with increased hospital mortality (OR [95% CI] of 1.34 [0.98-1.83]). VA-LRTI, often with difficult-to-treat bacteria, is frequent in patients admitted to the ICU due to severe COVID-19 and is associated with worse clinical outcomes, including higher mortality. Identifying risk factors for VA-LRTI might allow the early patient diagnosis to improve clinical outcomes. Trial registration: This is a prospective observational study; therefore, no health care interventions were applied to participants, and trial registration is not applicable