Rare

Potassium-40 is a widespread, naturally occurring isotope whose radioactivity impacts subatomic rare-event searches, nuclear structure theory, and estimated geological ages. A predicted electron-capture decay directly to the ground state of argon-40 has never been observed. The KDK (potassium decay) collaboration reports strong evidence of this rare decay mode. A blinded analysis reveals a nonzero ratio of intensities of ground-state electron-captures (I_{EC^{0}}) over excited-state ones (I_{EC^{*}}) of I_{EC^{0}}/I_{EC^{*}}=0.0095±[over stat]0.0022±[over sys]0.0010 (68% C.L.), with the null hypothesis rejected at 4σ. In terms of branching ratio, this signal yields I_{EC^{0}}=0.098%±[over stat]0.023%±[over sys]0.010%, roughly half of the commonly used prediction, with consequences for various fields [27L. Hariasz et al., companion paper, Phys. Rev. C 108, 014327 (2023)PRVCAN2469-998510.1103/PhysRevC.108.014327].

Determining g_{A}/g_{V} with High-Resolution Spectral Measurements Using a LiInSe_{2} Bolometer.

Neutrinoless double beta decay (0νßß) processes sample a wide range of intermediate forbidden nuclear transitions, which may be impacted by quenching of the axial vector coupling constant (g_{A}/g_{V}), the uncertainty of which plays a pivotal role in determining the sensitivity reach of 0νßß experiments. In this Letter, we present measurements performed on a high-resolution LiInSe_{2} bolometer in a "source=detector" configuration to measure the spectral shape of the fourfold forbidden ß decay of ^{115}In. The value of g_{A}/g_{V} is determined by comparing the spectral shape of theoretical predictions to the experimental ß spectrum taking into account various simulated background components as well as a variety of detector effects. We find evidence of quenching of g_{A}/g_{V} at >5σ with a model-dependent quenching factor of 0.655±0.002 as compared to the free-nucleon value for the interacting shell model. We also measured the ^{115}In half-life to be [5.18±0.06(stat)_{-0.015}^{+0.005}(sys)]×10^{14} yr within the interacting shell model framework. This Letter demonstrates the power of the bolometeric technique to perform precision nuclear physics single-ß decay measurements, which along with improved nuclear modeling can help reduce the uncertainties in the calculation of several decay nuclear matrix elements including those used in 0νßß sensitivity calculations.

High-Precision Q-Value Measurement Confirms the Potential of

The ground-state-to-ground-state ß-decay Q value of ^{135}Cs(7/2^{+})→^{135}Ba(3/2^{+}) has been directly measured for the first time. The measurement was done utilizing both the phase-imaging ion-cyclotron resonance technique and the time-of-flight ion-cyclotron resonance technique at the JYFLTRAP Penning-trap setup and yielded a mass difference of 268.66(30) keV between ^{135}Cs(7/2^{+}) and ^{135}Ba(3/2^{+}). With this very small uncertainty, this measurement is a factor of 3 more precise than the currently adopted Q value in the Atomic Mass Evaluation 2016. The measurement confirms that the first-forbidden unique ß^{-}-decay transition ^{135}Cs(7/2^{+})→^{135}Ba(11/2^{-}) is a candidate for antineutrino mass measurements with an ultralow Q value of 0.44(31) keV. This Q value is almost an order of magnitude smaller than those of nuclides presently used in running or planned direct (anti)neutrino mass experiment.

Discovery of an Exceptionally Strong ß-Decay Transition of

A significant fraction of stars between 7 and 11 solar masses are thought to become supernovae, but the explosion mechanism is unclear. The answer depends critically on the rate of electron capture on ^{20}Ne in the degenerate oxygen-neon stellar core. However, because of the unknown strength of the transition between the ground states of ^{20}Ne and ^{20}F, it has not previously been possible to fully constrain the rate. By measuring the transition, we establish that its strength is exceptionally large and that it enhances the capture rate by several orders of magnitude. This has a decisive impact on the evolution of the core, increasing the likelihood that the star is (partially) disrupted by a thermonuclear explosion rather than collapsing to form a neutron star. Importantly, our measurement resolves the last remaining nuclear physics uncertainty in the final evolution of degenerate oxygen-neon stellar cores, allowing future studies to address the critical role of convection, which at present is poorly understood.

Single and Double Beta-Decay Q Values among the Triplet

The atomic mass relations among the mass triplet ^{96}Zr, ^{96}Nb, and ^{96}Mo have been determined by means of high-precision mass measurements using the JYFLTRAP mass spectrometer at the IGISOL facility of the University of Jyväskylä. We report Q values for the ^{96}Zr single and double ß decays to ^{96}Nb and ^{96}Mo, as well as the Q value for the ^{96}Nb single ß decay to ^{96}Mo, which are Q_{ß}(^{96}Zr)=163.96(13), Q_{ßß}(^{96}Zr)=3356.097(86), and Q_{ß}(^{96}Nb)=3192.05(16) keV. Of special importance is the ^{96}Zr single ß-decay Q value, which has never been determined directly. The single ß decay, whose main branch is fourfold unique forbidden, is an alternative decay path to the ^{96}Zr ßß decay, and its observation can provide one of the most direct tests of the neutrinoless ßß-decay nuclear-matrix-element calculations, as these can be simultaneously performed for both decay paths with no further assumptions. The theoretical single ß-decay rate has been re-evaluated using a shell-model approach, which indicates a ^{96}Zr single ß-decay lifetime within reach of an experimental verification. The uniqueness of the decay also makes such an experiment interesting for an investigation into the origin of the quenching of the axial-vector coupling constant g_{A}.

Fecal calcium levels of bird nestlings as a potential indicator of species-specific metal sensitivity.

Sensitivity of bird species to environmental metal pollution varies but there is currently no general framework to predict species-specific sensitivity. Such information would be valuable from a conservation point-of-view. Calcium (Ca) has antagonistic effects on metal toxicity and studies with some common model species show that low dietary and circulating calcium (Ca) levels indicate higher sensitivity to harmful effects of toxic metals. Here we measured fecal Ca and five other macroelement (potassium K, magnesium Mg, sodium Na, phosphorus P, sulphur S) concentrations as proxies for dietary levels in 66 bird species to better understand their interspecific variation and potential use as an indicator of metal sensitivity in a wider range of species (the main analyses include 39 species). We found marked interspecific differences in fecal Ca concentration, which correlated positively with Mg and negatively with Na, P and S levels. Lowest Ca concentrations were found in insectivorous species and especially aerial foragers, such as swifts (Apodidae) and swallows (Hirundinidae). Instead, ground foraging species like starlings (Sturnidae), sparrows (Passeridae), cranes (Gruidae) and larks (Alaudidae) showed relatively high fecal Ca levels. Independent of phylogeny, insectivorous diet and aerial foraging seem to indicate low Ca levels and potential sensitivity to toxic metals. Our results, together with information published on fecal Ca levels and toxic metal impacts, suggest that fecal Ca levels are a promising new tool to evaluate potential metal-sensitivity of birds, and we encourage gathering such information in other bird species. Information on the effects of metals on breeding parameters in a wider range of bird species would also help in ranking species by their sensitivity to metal pollution.

Association between host's genetic diversity and parasite burden in damselflies.

Recent research indicates that low genetic variation in individuals can increase susceptibility to parasite infection, yet evidence from natural invertebrate populations remains scarce. Here, we studied the relationship between genetic heterozygosity, measured as AFLP-based inbreeding coefficient fAFLP , and gregarine parasite burden from eleven damselfly, Calopteryx splendens, populations. We found that in the studied populations, 5-92% of males were parasitized by endoparasitic gregarines (Apicomplexa: Actinocephalidae). Number of parasites ranged from none to 47 parasites per male, and parasites were highly aggregated in a few hosts. Mean individual fAFLP did not differ between populations. Moreover, we found a positive association between individual's inbreeding coefficient and parasite burden. In other words, the more homozygous the individual, the more parasites it harbours. Thus, parasites are likely to pose strong selection pressure against inbreeding and homozygosity. Our results support the heterozygosity-fitness correlation hypothesis, which suggests the importance of heterozygosity for an individual's pathogen resistance.

Sympatric shift in a male sexual ornament in the damselfly Calopteryx splendens.

Character displacement is a process by which interactions between two species that exhibit similar traits, results in geographical patterns of trait divergence in one or both species. These traits evolve to reduce costs of interspecific interactions in sympatry and thus differ from their condition in allopatry. In male damselflies Calopteryx splendens, large wing spots are sexually selected. However, in sympatric populations with Calopteryx virgo, wing spot size decreases as C. virgo abundance increases. The stability of this pattern is unclear, because previous studies have focused on sympatric populations with potentially fluctuating relative abundances. We studied the wing spot sizes of C. splendens in both sympatric and allopatric populations. Our data show that male C. splendens' wing spots are larger in allopatry than in sympatry with C. virgo. We suggest that both interspecific aggression and avoidance of interspecific reproductive interactions may result in this pattern, although their relative importance remains unclear.

Sympathetic neurons outlive the original host after transplantation to the rat submandibular gland.

Sympathetic ganglion tissue of aged (36 months) Wistar rats was allotransplanted into the submandibular gland (SMG) of young (3 months) animals to study whether sympathetic neurons can outlive the original host. The viability of the transplants was evaluated one year postgrafting, using the formaldehyde-induced fluorescence technique (FIF) for histochemical demonstration of catecholamines, tyrosine hydroxylase (TH) immunohistochemistry, and morphometry. One year after transplantation, grafted superior cervical ganglion (SCG) cells demonstrated catecholamine fluorescence and tyrosine hydroxylase immunoreactivity. The transplants consisted of groups of sympathetic neurons dispersed in a fibrous matrix. After long postgrafting time, the sympathetic neurons of aged rats showed several signs of enhanced degeneration; increased autofluorescent lipopigment, decreased neuronal density and reduced catecholamine fluorescence. The mean diameter of the transplanted aged neurons was significantly decreased. The histograms of grouped diameter values showed a shift to smaller cells in ganglion transplants. A subpopulation of small and medium-sized grafted neurons sent out fluorescent fibers, which were located in a fibrous scar area but did not extend into submandibular host tissue. The results indicate that a long postgrafting time induced degeneration which is comparable to normal aging changes in grafted very old neurons. Thus, aged sympathetic neurons maintain plasticity to survive as transplants, and under favourable conditions these neurons outlive the original host.

Fitness consequences of hoarding behaviour in the Eurasian red squirrel.

Hoarding increases food availability during periods of scarcity, and therefore should enhance fitness. Although short-term advantages of hoarding have been described for birds, effects over an animal's lifetime have not yet been documented. Here, we report that in the red squirrel, Sciurus vulgaris, individuals which recovered many cached tree seeds increased their body mass and were more likely to survive the spring breeding season than those that recovered fewer seeds. There was no significant effect of the time spent recovering cached food on the probability for females to produce a spring litter. In the long-term, hoarding behaviour was related to fitness in two ways; (i) squirrels spending more time recovering hoards survived longer; and (ii) females with a high recovery activity tended to wean more young in their lifetime than those that spent less time recovering hoards. Our data indicate that in red squirrels, food hoarding is an adaptive foraging strategy to preserve temporarily abundant food resources for future periods of hardship, and that individuals that hoard and recovery many tree seeds are more likely to survive and reproduce.

Immunocompetence, developmental stability and wingspot size in the damselfly Calopteryx splendens L.

Calopteryx splendens males exhibit a remarkable variation in wing pigmentation both within and between populations. In this study, we examined whether the wingspots of male C. splendens are related to male quality. We measured the nylon implant encapsulation rate for 85 males and found that males with larger wingspots had a faster encapsulation rate, indicating a better immunocompetence. We also found that the encapsulation rate was positively correlated with the density of haemocytes in the haemolymph. Another measurement of male quality, fluctuating asymmetry of wingspots, correlated negatively with the size of the wingspots. Males with asymmetrical wingspots also had lower encapsulation rates than more symmetrical males. Our results suggest that the size of wingspot is an indicator of male quality in C. splendens.

Hot spots, indicator taxa, complementarity and optimal networks of taiga.

If hot spots for different taxa coincide, priority-setting surveys in a region could be carried out more cheaply by focusing on indicator taxa. Several previous studies show that hot spots of different taxa rarely coincide. However, in tropical areas indicator taxa may be used in selecting complementary networks to represent biodiversity as a whole. We studied beetles (Coleoptera), Heteroptera, polypores or bracket fungi (Polyporaceae) and vascular plants of old growth boreal taiga forests. Optimal networks for Heteroptera maximized the high overall species richness of beetles and vascular plants, but these networks were least favourable options for polypores. Polypores are an important group indicating the conservation value of old growth taiga forests. Random selection provided a better option. Thus, certain groups may function as good indicators for maximizing the overall species richness of some taxonomic groups, but all taxa should be examined separately.

Viability of adrenal chromaffin cells in the superior cervical ganglion of young adult and aged rats.

Adrenal medullary tissue was autotransplanted to the superior cervical ganglion (SCG) of aged (26 months old) and young adult (3 months old) rats. Four and 20 weeks after operation, the viability of the transplants was evaluated using the formaldehyde-induced fluorescence (FIF) technique and tyrosine hydroxylase (TH) immunocytochemistry. Four weeks postgrafting, the transplant consisted of a densely-packed group of intensively fluorescent chromaffin cells in both age groups. The cells showed strong TH immunoreactivity and some of them were elongated, but only a few displayed short processes. At 20 weeks, most of the cells were spindle shaped and sent out fluorescent processes and a few of them were transformed toward ganglion-like cells. The results suggest that both young and old adrenal chromaffin cells are able to survive, produce neuronal processes and transform toward a neuronal phenotype in the rat superior cervical ganglion.

Normal CSF neuron-specific enolase and S-100 protein levels in patients with recent non-complicated tonic-clonic seizures.

PURPOSE: Increased concentrations of the nervous-system-specific proteins neuron-specific enolase (NSE) and S-100 protein (S-100) have been measured with lesions in the CNS. Elevated levels of serum NSE (s-NSE) have been found in status epilepticus, but also after single epileptic seizures. Because larger studies addressing cerebrospinal fluid (CSF) levels of NSE or S-100 have not been performed, we measured CSF NSE and S-100 after tonic-clonic seizures to search for evidence of neuronal and glial damage. METHODS: 22 consecutive patients with single, previously undiagnosed and untreated tonic-clonic seizures were studied. Serum and CSF samples were collected within 24 h after seizure. 18 serum and CSF samples were measured from a control group. RESULTS: The mean CSF NSE was 8.9 ng/ml (range 0-28 ng/ml) and s-NSE 8.2 ng/ml (range 5-15 ng/ml) in the patient group. The mean concentrations in the control group were 13.1 ng/ml (range 3-24 ng/ml) and 8.0 ng/ml (range 5-12 ng/ml) respectively. The mean CSF S-100 was 3.17 microg/l (range 1.45-7.02 microg/l) and serum S-100 0.05 microg/l (range 0-0.32 microg/l), and in controls 3.19 microg/l (range 1.52-5.13 microg/l) and 0.08 microg/l (range 0-0.28 microg/l). CONCLUSION: There were no significant differences between the mean concentrations of NSE or S-100 in CSF and serum between the epileptic group and controls. These results do not confirm the previous observation of elevated NSE-levels after tonic-clonic seizures, which argues against neuronal or glial damage after uncomplicated tonic-clonic seizures in unmedicated patients.

Interleukin-6 and interleukin-1 receptor antagonist in cerebrospinal fluid from patients with recent tonic-clonic seizures.

We have previously reported increased concentrations of interleukin (1L)-6 in CSF from patients with tonic-clonic seizures, where increased cytokine production most likely is a consequence of neuronal epileptic activity associated with seizures. The biological effects of IL-6 are mediated by other cytokines, which are studied here in addition to IL-6. The purpose of this study was to analyze levels of soluble cytokines from plasma and CSF from patients with newly developed tonic-clonic seizures. The concentrations of IL-6, IL-1 receptor antagonist (IL-1RA), IL-1beta, tumor necrosis factor (TNFalpha) and nerve growth factor (NGF) were measured from plasma and CSF from 22 patients with newly developed tonic-clonic seizures within 24 h from the seizure and 18 controls. The mean concentrations of IL-6 were significantly increased in CSF (P<0.001) and plasma (P<0.01) after tonic-clonic seizures, there was some indication of increased concentrations of IL-1RA and no significant change in NGF, IL-1beta or TNFalpha. Our study shows that cytokine network is activated in patients after recent tonic-clonic seizures. We provide evidence of intrathecal production of IL-6 associated with electrical seizure activity.

Next generation fluidized bed granulator automation.

A system for fluidized bed granulator automation with in-line multichannel near infrared (NIR) moisture measurement and a unique air flow rate measurement design was assembled, and the information gained was investigated. The multivariate process data collected was analyzed using principal component analysis (PCA). The test materials (theophylline and microcrystalline cellulose) were granulated and the calibration behavior of the multichannel NIR set-up was evaluated against full Fourier Transform (FT) NIR spectra. Accurate and reliable process air flow rate measurement proved critical in controlling the granulation process. The process data describing the state of the process was projected in two dimensions, and the information from various trend charts was outlined simultaneously. The absorbence of test material at correction wavelengths (NIR region) and the nature of material-water interactions affected the detected in-line NIR water signal. This resulted in different calibration models for the test materials. Development of process analytical methods together with new data visualization algorithms creates new tools for in-process control of the fluidized bed granulation.

Mutans streptococci and their specific oral target. New implications to prevent dental caries?

Over the past 25 years collection and analysis of clinical, dietary and microbiological data have led to the conclusion that caries is a bacterial infection, initiated by mutans streptococci which can be transmitted within a family by saliva. Bacteria attach themselves selectively to various oral surfaces. In order to inhabit the mouth mutans streptococci require the presence of teeth. The targets of the odontopathogens (tooth hard substances and gingival sulcus) appear into the oral cavity on a "peculiar" way: these surfaces and tissues are not exposed to bacterial colonization from birth as skin and mucosa. Teething starts 8 +/- 2 months after birth at which age the infant's antibody-dependent defence system is physiologically weak. Teeth erupt slowly during the night, at a period of least intraoral activity. Theoretically, streptococcal colonization can begin as soon as a few mm2 of incisal edges of primary teeth become visible. The earlier the establishment of mutans streptococci in the plaque of the primary teeth, the earlier and more extensive is the caries development. These aspects might open new possibilities for the prevention of the dental diseases, provided that means are found by which the primary colonization can be hindered or postponed.

Release of preventive agents from pacifiers in vitro. An introduction to a novel preventive measure.

Clinical data show that the later primary teeth are colonized by mutans streptococci (MS), the less caries will develop, if at all. Since up to 90% of teething children develop a sucking habit, pacifiers were designed to release preventive agents into the mouth. Simultaneous use of sodium fluoride and xylitol increases the enamel fluoride content. Xylitol affects specifically growth and metabolism of mutans streptococci. The aim of this study was to determine the release of fluoride, xylitol and sorbitol from pacifiers in vitro. A disintegration apparatus was designed to test the dissolution of tablets containing NaF resp. 0.25 mg F, 160 mg xylitol and 150 mg sorbitol from the pacifiers. Six pacifiers were agitated simultaneously with a standardised pump movement, 30 strokes/min, in 15 ml normal saline at +37 degrees C for 2, 5, 10, 20, 40, 60 and 90 min. The released fluoride was determined in 1 ml samples of saline to which 1 ml Tisab was added using a combined F-ion electrode. Xylitol and sorbitol were analyzed by using an ion chromatograph with a pulsed-amperometric detector. A linear slow release of fluoride, xylitol and sorbitol from the pacifiers could be observed up to 90 min. After 2700 strokes the residual saline in the suction chambers (vol. approximately 0.4 ml) was equally analyzed, where all 3 ingredients could still be detected.