11 research outputs found
Conservation of energy-momentum of matter as the basis for the gauge theory of gravitation
According to Yang \& Mills (1954), a {\it conserved} current and a related
rigid (`global') symmetry lie at the foundations of gauge theory. When the
rigid symmetry is extended to a {\it local} one, a so-called gauge symmetry, a
new interaction emerges as gauge potential ; its field strength is . In gravity, the conservation of the energy-momentum current of
matter and the rigid translation symmetry in the Minkowski space of special
relativity lie at the foundations of a gravitational gauge theory. If the
translation invariance is made local, a gravitational potential
arises together with its field strength . Thereby
the Minkowski space deforms into a Weitzenb\"ock space with nonvanishing
torsion but vanishing curvature. The corresponding theory is reviewed and
its equivalence to general relativity pointed out. Since translations form a
subgroup of the Poincar\'e group, the group of motion of special relativity,
one ought to straightforwardly extend the gauging of the translations to the
gauging of full Poincar\'e group thereby also including the conservation law of
the {\it angular momentum} current. The emerging Poincar\'e gauge (theory of)
gravity, starting from the viable Einstein-Cartan theory of 1961, will be
shortly reviewed and its prospects for further developments assessed.Comment: 46 pages, 4 figures, minor corrections, references added,
contribution to "One Hundred Years of Gauge Theory" edited by S. De Bianchi
and C. Kiefe
Cerebrospinal fluid Plasmodium falciparum histidine-rich protein-2 in pediatric cerebral malaria
Abstract Background Cerebral malaria (CM) causes a rapidly developing coma, and remains a major contributor to morbidity and mortality in malaria-endemic regions. This study sought to determine the relationship between cerebrospinal fluid (CSF) Plasmodium falciparum histidine rich protein-2 (PfHRP-2) and clinical, laboratory and radiographic features in a cohort of children with retinopathy-positive CM. Methods Patients included in the study were admitted (2009â2013) to the Pediatric Research Ward (Queen Elizabeth Central Hospital, Blantyre, Malawi) meeting World Health Organization criteria for CM with findings of malarial retinopathy. Enzyme-linked immunosorbent assay was used to determine plasma and CSF PfHRP-2 levels. Wilcoxon rank-sum tests and multivariable logistic regression analysis assessed the association of clinical and radiographic characteristics with the primary outcome of death during hospitalization. Results In this cohort of 94 patients, median age was 44 (interquartile range 29â62) months, 53 (56.4%) patients were male, 6 (7%) were HIV-infected, and 10 (11%) died during hospitalization. Elevated concentrations of plasma lactate (pâ=â0.005) and CSF PfHRP-2 (pâ=â0.04) were significantly associated with death. On multivariable analysis, higher PfHRP-2 in the CSF was associated with death (odds ratio 9.00, 95% confidence interval 1.44â56.42) while plasma PfHRP-2 was not (odds ratio 2.05, 95% confidence interval 0.45â9.35). Conclusions Elevation of CSF, but not plasma PfHRP-2, is associated with death in this paediatric CM cohort. PfHRP-2 egress into the CSF may represent alteration of blood brain barrier permeability related to the sequestration of parasitized erythrocytes in the cerebral microvasculature
An inducible expression system in the alga Nannochloropsis gaditana controlled by the nitrate reductase promoter
mRNA Profiling Reveals Determinants of Trastuzumab Efficiency in HER2-Positive Breast Cancer
Advances in Genetic Engineering of Microalgae
Hallmann A. Advances in Genetic Engineering of Microalgae. In: Grand Challenges in Algae Biotechnology. Grand Challenges in Biology and Biotechnology. Cham: Springer International Publishing; 2020: 159-221