206 research outputs found
Magnetized baryons and the QCD phase diagram: NJL model meets the lattice
We determine the baryon spectrum of 1 + 1 + 1-flavor QCD in the presence of
strong background magnetic fields using lattice simulations at physical quark
masses for the first time. Our results show a splitting within multiplets
according to the electric charge of the baryons and reveal, in particular, a
reduction of the nucleon masses for strong magnetic fields. This
first-principles input is used to define constituent quark masses and is
employed to set the free parameters of the Polyakov loop-extended
Nambu-Jona-Lasinio (PNJL) model in a magnetic field-dependent manner. The so
constructed model is shown to exhibit inverse magnetic catalysis at high
temperatures and a reduction of the transition temperature as the magnetic
field grows - in line with non-perturbative lattice results. This is contrary
to the naive variant of this model, which gives incorrect results for this
fundamental phase diagram. Our findings demonstrate that the magnetic field
dependence of the PNJL model can be reconciled with the lattice findings in a
systematic way, employing solely zero-temperature first-principles input.Comment: 14 pages, 7 figures, updatet some figures, included new references
and a table of key result
Isolation of Radial Glia-Like Neural Stem Cells from Fetal and Adult Mouse Forebrain via Selective Adhesion to a Novel Adhesive Peptide-Conjugate
Preferential adhesion of neural stem cells to surfaces covered with a novel synthetic adhesive polypeptide (AK-cyclo[RGDfC]) provided a unique, rapid procedure for isolating radial glia-like cells from both fetal and adult rodent brain. Radial glia-like (RGl) neural stem/progenitor cells grew readily on the peptide-covered surfaces under serum-free culture conditions in the presence of EGF as the only growth factor supplement. Proliferating cells derived either from fetal (E 14.5) forebrain or from different regions of the adult brain maintained several radial glia-specific features including nestin, RC2 immunoreactivity and Pax6, Sox2, Blbp, Glast gene expression. Proliferating RGl cells were obtained also from non-neurogenic zones including the parenchyma of the adult cerebral cortex and dorsal midbrain. Continuous proliferation allowed isolating one-cell derived clones of radial glia-like cells. All clones generated neurons, astrocytes and oligodendrocytes under appropriate inducing conditions. Electrophysiological characterization indicated that passive conductance with large delayed rectifying potassium current might be a uniform feature of non-induced radial glia-like cells. Upon induction, all clones gave rise to GABAergic neurons. Significant differences were found, however, among the clones in the generation of glutamatergic an
Thermal QCD in a non-uniform magnetic background
Off-central heavy-ion collisions are known to feature magnetic fields with
magnitudes and characteristic gradients corresponding to the scale of the
strong interactions. In this work, we employ equilibrium lattice simulations of
the underlying theory, QCD, involving similar inhomogeneous magnetic field
profiles to achieve a better understanding of this system. We simulate three
flavors of dynamical staggered quarks with physical masses at a range of
magnetic fields and temperatures, and extrapolate the results to the continuum
limit. Analyzing the impact of the field on the quark condensate and the
Polyakov loop, we find non-trivial spatial features that render the QCD medium
qualitatively different as in the homogeneous setup, especially at temperatures
around the transition. In addition, we construct leading-order chiral
perturbation theory for the inhomogeneous background and compare its prediction
to our lattice results at low temperature. Our findings will be useful to
benchmark effective theories and low-energy models of QCD for a better
description of peripheral heavy-ion collisions.Comment: 24 pages, 15 figure
Spinel ferrite nanocrystals embedded inside ZnO: magnetic, electronic and magneto-transport properties
In this paper we show that spinel ferrite nanocrystals (NiFe2O4, and CoFe2O4)
can be texturally embedded inside a ZnO matrix by ion implantation and
post-annealing. The two kinds of ferrites show different magnetic properties,
e.g. coercivity and magnetization. Anomalous Hall effect and positive
magnetoresistance have been observed. Our study suggests a
ferrimagnet/semiconductor hybrid system for potential applications in
magneto-electronics. This hybrid system can be tuned by selecting different
transition metal ions (from Mn to Zn) to obtain various magnetic and electronic
properties.Comment: 12 pages, 14 figs. accepted for publication at PR
The genus Myrmica Latreille, 1804 (Hymenoptera: Formicidae) in Romania : distribution of species and key for their identification
Genus Myrmica is one of the largest ant genera in Romania with 18 species distributed across the entire country. In
the frame of this study we present the distribution data of all Romanian Myrmica species: M. bergi, M. constricta, M. gallienii, M.
hellenica, M. lobicornis, M. lonae, M. karavajevi, M. rubra, M. ruginodis, M. rugulosa, M. sabuleti, M. salina, M. scabrinodis, M.
schencki, M. slovaca, M. specioides, M. sulcinodis and M. vandeli. Four species are reported for the first time in the Romanian fauna:
M. bergi, M. constricta, M. gallienii and M. karavajevi, while the occurrence of several species is probable. These species are listed
separately. In addition, a key to the worker caste of Myrmica (with the use of male characters for some species) is provided, including
species with likely occurrence in Romania
Effects of climate variation on bird escape distances modulate community responses to global change
Warm thanks to Jacqui Sykoff for substantially improving the readability of former versions of the manuscript. GM was supported by the Hungarian Ministry for Innovation and Technology within the framework of the Thematic Excellence Programme 2020 (TKP2020-IKA-12, TKP2020-NKA-16).. KT was supported by institutional research funding IUT (34-8) of the Estonian Ministry of Education and Research. This paper is a contribution to the project URBILAND (PID2019-107423GA-I00/SRA 1013039/501100011033), funded by the Spanish Research Agency.Climate and land use are rapidly changing environmental conditions. Behavioral responses to such global perturbations can be used to incorporate interspecific interactions into predictive models of population responses to global change. Flight initiation distance (FID) reflects antipredator behaviour defined as the distance at which an individual takes flight when approached by a human, under standardized conditions. This behavioural trait results from a balance between disturbance, predation risk, food availability and physiological needs, and it is related to geographical range and population trends in European birds. Using 32,145 records of flight initiation distances for 229 bird species during 2006-2019 in 24 European localities, we show that FIDs decreased with increasing temperature and precipitation, as expected if foraging success decreased under warm and humid conditions. Trends were further altered by latitude, urbanisation and body mass, as expected if climate effects on FIDs were mediated by food abundance and need, differing according to position in food webs, supporting foraging models. This provides evidence for a role of behavioural responses within food webs on how bird populations and communities are affected by global change.Hungarian Ministry for Innovation and Technology TKP2020-IKA-12
TKP2020-NKA-16Ministry of Education and Research, Estonia 34-8Spanish Research Agency PID2019-107423GA-I00/SRA 1013039/50110001103
Transient receptor potential vanilloid 4 channel deficiency aggravates tubular damage after acute renal ischaemia reperfusion
Transient receptor potential vanilloid 4 (TRPV4) cation channels are functional in all renal vascular segments and mediate endothelium-dependent vasorelaxation. Moreover, they are expressed in distinct parts of the tubular system and activated by cell swelling. Ischaemia/reperfusion injury (IRI) is characterized by tubular injury and endothelial dysfunction. Therefore, we hypothesised a putative organ protective role of TRPV4 in acute renal IRI. IRI was induced in TRPV4 deficient (Trpv4 KO) and wild-type (WT) control mice by clipping the left renal pedicle after right-sided nephrectomy. Serum creatinine level was higher in Trpv4 KO mice 6 and 24 hours after ischaemia compared to WT mice. Detailed histological analysis revealed that IRI caused aggravated renal tubular damage in Trpv4 KO mice, especially in the renal cortex. Immunohistological and functional assessment confirmed TRPV4 expression in proximal tubular cells. Furthermore, the tubular damage could be attributed to enhanced necrosis rather than apoptosis. Surprisingly, the percentage of infiltrating granulocytes and macrophages were comparable in IRI-damaged kidneys of Trpv4 KO and WT mice. The present results suggest a renoprotective role of TRPV4 during acute renal IRI. Further studies using cell-specific TRPV4 deficient mice are needed to clarify cellular mechanisms of TRPV4 in IRI
Enhanced Ca(2+) signaling, mild primary aldosteronism, and hypertension in a familial hyperaldosteronism mouse model (Cacna1h(M1560V/+))
Gain-of-function mutations in the CACNA1H gene (encoding the T-type calcium channel Ca(V)3.2) cause autosomal-dominant familial hyperaldosteronism type IV (FH-IV) and early-onset hypertension in humans. We used CRISPR/Cas9 to generate Cacna1h(M1560V/+) knockin mice as a model of the most common FH-IV mutation, along with corresponding knockout mice (Cacna1h(-/-)). Adrenal morphology of both Cacna1h(M1560V/+) and Cacna1h(-/-) mice was normal. Cacna1h(M1560V/+) mice had elevated aldosterone:renin ratios (a screening parameter for primary aldosteronism). Their adrenal Cyp11b2 (aldosterone synthase) expression was increased and remained elevated on a high-salt diet (relative autonomy, characteristic of primary aldosteronism), but plasma aldosterone was only elevated in male animals. The systolic blood pressure of Cacna1h(M1560V/+) mice was 8 mmHg higher than in wild-type littermates and remained elevated on a high-salt diet. Cacna1h(-/-) mice had elevated renal Ren1 (renin-1) expression but normal adrenal Cyp11b2 levels, suggesting that in the absence of Ca(V)3.2, stimulation of the renin-angiotensin system activates alternative calcium entry pathways to maintain normal aldosterone production. On a cellular level, Cacna1h(M1560V/+) adrenal slices showed increased baseline and peak intracellular calcium concentrations in the zona glomerulosa compared to controls, but the frequency of calcium spikes did not rise. We conclude that FH-IV, on a molecular level, is caused by elevated intracellular Ca(2+) concentrations as a signal for aldosterone production in adrenal glomerulosa cells. We demonstrate that a germline Cacna1h gain-of-function mutation is sufficient to cause mild primary aldosteronism, whereas loss of Ca(V)3.2 channel function can be compensated for in a chronic setting
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