On the astronomical origin of the Hallstatt oscillation found in radiocarbon and climate records throughout the Holocene

An oscillation with a period of about 2100-2500 years, the Hallstatt cycle, is found in cosmogenic radioisotopes (C-14 and Be-10) and in paleoclimate records throughout the Holocene. Herein we demonstrate the astronomical origin of this cycle. Namely, this oscillation is coherent to the major stable resonance involving the four Jovian planets - Jupiter, Saturn, Uranus and Neptune - whose period is p=2318 yr. The Hallstatt cycle could derive from the rhythmic variation of the circularity of the solar system disk assuming that this dynamics could eventually modulate the solar wind and, consequently, the incoming cosmic ray flux and/or the interplanetary/cosmic dust concentration around the Earth-Moon system. The orbit of the planetary mass center (PMC) relative to the Sun is used as a proxy. We analyzed how the instantaneous eccentricity vector of this virtual orbit varies from 13,000 B. C. to 17,000 A. D.. We found that it undergoes kind of pulsations as it clearly presents rhythmic contraction and expansion patterns with a 2318 yr period together with a number of already known faster oscillations associated to the planetary orbital stable resonances. We found that a fast expansion of the Sun-PMC orbit followed by a slow contraction appears to prevent cosmic rays to enter within the system inner region while a slow expansion followed by a fast contraction favors it. Similarly, the same dynamics could modulate the amount of interplanetary/cosmic dust falling on Earth. These would then cause both the radionucleotide production and climate change by means of a cloud/albedo modulation. Other stable orbital resonance frequencies (e.g. at periods of 20 yr, 45 yr, 60 yr, 85 yr, 159-171-185 yr, etc.) are found in radionucleotide, solar, aurora and climate records, as determined in the scientific literature. Thus, the result supports a planetary theory of solar and/or climate variation.Comment: 36 pages, 14 figures, 1 tabl

Stand-alone wearable system for ubiquitous real-time monitoring of muscle activation potentials

Wearable technology is attracting most attention in healthcare for the acquisition of physiological signals. We propose a stand-alone wearable surface ElectroMyoGraphy (sEMG) system for monitoring the muscle activity in real time. With respect to other wearable sEMG devices, the proposed system includes circuits for detecting the muscle activation potentials and it embeds the complete real-time data processing, without using any external device. The system is optimized with respect to power consumption, with a measured battery life that allows for monitoring the activity during the day. Thanks to its compactness and energy autonomy, it can be used outdoor and it provides a pathway to valuable diagnostic data sets for patients during their own day-life. Our system has performances that are comparable to state-of-art wired equipment in the detection of muscle contractions with the advantage of being wearable, compact, and ubiquitous

Estimation of Photovoltaic Generation Forecasting Models using Limited Information

This work deals with the problem of estimating a photovoltaic generation forecasting model in scenarios where measurements of meteorological variables (i.e. solar irradiance and temperature) at the plant site are not available. A novel algorithm for the estimation of the parameters of the well-known PVUSA model of a photovoltaic plant is proposed. Such a method is characterized by a low computational complexity, and efficiently exploits only power generation measurements, a theoretical clear-sky irradiance model, and temperature forecasts provided by a meteorological service. An extensive experimental validation of the proposed method on real data is also presented

Large Eddy Simulation of a Bluff Body Stabilized Lean Premixed Flame

The present study is devoted to verify current capabilities of Large Eddy Simulation (LES) methodology in the modeling of lean premixed flames in the typical turbulent combustion regime of Dry Low NOx gas turbine combustors. A relatively simple reactive test case, presenting all main aspects of turbulent combustion interaction and flame stabilization of gas turbine lean premixed combustors, was chosen as an affordable test to evaluate the feasibility of the technique also in more complex test cases. A comparison between LES and RANS modeling approach is performed in order to discuss modeling requirements, possible gains, and computational overloads associated with the former. Such comparison comprehends a sensitivity study to mesh refinement and combustion model characteristic constants, computational costs, and robustness of the approach. In order to expand the overview on different methods simulations were performed with both commercial and open-source codes switching from quasi-2D to fully 3D computations

Isolation and genetic identification of spore-forming bacteria associated with concentrated-milk processing in Nebraska

Spore-forming bacteria are heat-resistant microorganisms capable of surviving and germinating in milk after pasteurization. They have been reported to affect the quality of dairy products by the production of enzymes (lipolytic and proteolytic) under low-temperature conditions in fluid milk, and have become a limiting factor for milk powder in reaching some selective markets. The objective of this research was to isolate and identify the population of spore-forming bacteria (psychrotrophic and thermophilic strains) associated with concentrated milk processing in Nebraska. During 2 seasons, in-process milk samples from a commercial plant (raw, pasteurized, and concentrated) were collected and heat-treated (80°C/12 min) to recover only spore-formers. Samples were spread-plated using standard methods agar and incubated at 32°C to enumerate mesophilic spore counts. Heat-treated samples were also stored at 7°C and 55°C to recover spore-formers that had the ability to grow under those temperature conditions. Isolates obtained from incubation or storage conditions were identified using molecular techniques (16S or rpoB sequencing). Based on the identification of the isolates and their relatedness, strains found in raw, pasteurized, and concentrated milk were determined to be similar. Paenibacillus spp. were associated with both raw and concentrated milk. Due to their known ability to cause spoilage under refrigeration, this shows the potential risk associated with the transferring of these problematic organisms into other dairy products. Other Bacillus species found in concentrated milk included Bacillus clausii, Bacillus subtilis, Lysinibacillus sp., Bacillus safensis, Bacillus licheniformis, Bacillus sonorensis, and Brevibacillus sp., with the last 3 organisms being capable of growing at thermophilic temperatures. These strains can also be translocated to other dairy products, such as milk powder, representing a quality problem. The results of this research highlight the importance of understanding spore-formers associated with the processing of condensed milk, which then may allow for specific interventions to be applied to control these microorganisms in this processing chain. To our knowledge, this is the first study evaluating spore-formers associated with concentrated milk in the United States

SPECTROSCOPIC STUDY OF Q CYGNI: SURPRISES FROM AN OLD NOVA

We present a time-resolved spectroscopic study of Q Cyg (Nova Cyg 1876), determining a period of P = 10.08 hr for the system. Our data also reveal P Cygni profiles in the He I λλ5876 and 7065 lines and occasionally in the Hα line. Although P Cygni profiles commonly appear in the UV resonance lines of novalike cataclysmic variables, only BZ Cam was previously known to exhibit a rapidly variable wind, which leaves its signature in time-resolved optical spectral lines. A comparison between BZ Cam and Q Cyg reveals striking similarities between the two systems. The origin of the outflow in Q Cyg and a possible correlation of the P Cygni profiles with the system's optical state are discussed

Assessing Topographical Orientation Skills in Cannabis Users

The long-term effects of cannabis on human cognition are still unclear, but, considering that cannabis is a widely used substance and, overall, its potential use in therapeutic interventions, it is important to evaluate them. We hypothesize that the discrepancies among studies could be attributed to the specific cognitive function investigated and that skills subserved by the hippocampus, such as the spatial orientation abilities and, specifically, the ability to form and use cognitive maps, should be more compromised than others. Indeed it has been showed that cannabis users have a reduced hippocampus and that the hippocampus is the brain region in which cannabis has the greatest effect since it contains the highest concentration of cannabinoid receptors. To test this hypothesis we asked 15 heavy cannabis users and 19 nonusers to perform a virtual navigational test, the CMT, that assesses the ability to form and use cognitive maps. We found that using cannabis has no effect on these hippocampus-dependent orientation skills. We discuss the implications of our findings and how they relate to evidence reported in the literature that the intervention of functional reorganization mechanisms in cannabis user allows them to cope with the cognitive demands of navigational tasks

Typical examples of classical novae

Because of the very complicated individualistic behavior of each nova, we think it necessary to review the observations of a few well-observed individuals. We have selected a few objects of different speed classes, which have been extensively observed. They are: V1500 Cygni 1975, a very fast nova; V603 Aql 1918, fast nova; CP Pup 1942, fast nova; GK Per 1901, fast nova; V 1668 Cyg 1979, moderately fast nova; FH Ser 1970, slow nova; DQ Her 1934, slow nova; T Aur 1891, slow nova; RR Pic 1925, slow nova; and HR Del 1967, very slow nova