Making An Observation Without Making An Observation: “Seeing” Knowledge Embedded In The Physical World With One’s Own Eyes

In electron shelving, one kind of quantum jump in which an electron in an atom moves in a discontinuous fashion to another energy level, a person can "see" knowledge that a weak transition (which is very slow) has occurred since it is proven that a strong transition (which is very fast) has not occurred in the time in which the strong transition can occur. This is a null measurement. There is no physical detection of the photon in the weak transition. There is only the logical deduction that the weak transition occurred since one cannot detect the photon in the strong transition, the only other possible transition. Looking at the interruption in the fluorescence that occurs in the strong transition, a “dark” interval, is "seeing" the knowledge resulting from the logical deduction. The significance of a null measurement in leading to the conclusion that one can "see" the knowledge resulting from a logical deduction is discussed. The null measurement in the weak transition is one form of Einstein’s spooky action where something not physical occurring in the possible strong transition leads to the occurrence of the weak transition. (2021 April Meeting of the American Physical Society, https://meetings.aps.org/Meeting/APR21/Session/KP01.48)

Rhynchonelliform brachiopods and trilobites of the ‘upper dark interval’ in the koněprusy area (Devonian, Eifelian, Kačák Event; the Czech Republic)

The dark pelbiodetrital limestone beds of the ‘upper dark interval’ in the Koněprusy area, Central Bohemia, the Czech Republic, the assumed manifestation of the Kačák Event in this area, yielded a moderately diverse faunule of rhynchonelliform brachiopods and trilobites. In total, 15 species have been recognized (13 brachiopods and 2 trilobites), but the majority of them are only tentatively determined to generic level due to fragmentation, rarity or poor preservation. Brachiopod genera Leptaenopyxis, Protodouvillina, Douvillinella, Holynetes, Poloniproductus, Iridistrophia, Mystrophora, Pentamerella, Quasidavidsonia, Carinatina, Mimatrypa, Leptathyris, Eoreticularia and a single trilobite Astycoryphe were determined. The mode of preservation indicates transport of skeletal bioclasts from shallower parts of the basin and their fragmentation in debris flows together with fragments of terrestrial plants, crinoid detritus and numerous pelagic fossils, especially the dacryoconarid Nowakia ex gr. otomari. Associated conodonts (as well as trilobites) indicate a late Eifelian age for the fauna (Polygnathus ensensis Zone).

Light-dependent magnetoreception in birds: the crucial step occurs in the dark

The Radical Pair Model proposes that the avian magnetic compass is based on spin-chemical processes: since the ratio between the two spin states singlet and triplet of radical pairs depends on their alignment in the magnetic field, it can provide information on magnetic directions. Cryptochromes, blue light-absorbing flavoproteins, with flavin adenine dinucleotide as chromophore, are suggested as molecules forming the radical pairs underlying magnetoreception. When activated by light, cryptochromes undergo a redox cycle, in the course of which radical pairs are generated during photo-reduction as well as during light-independent re-oxidation. This raised the question as to which radical pair is crucial for mediating magnetic directions. Here, we present the results from behavioural experiments with intermittent light and magnetic field pulses that clearly show that magnetoreception is possible in the dark interval, pointing to the radical pair formed during flavin re-oxidation. This differs from the mechanism considered for cryptochrome signalling the presence of light and rules out most current models of an avian magnetic compass based on the radical pair generated during photo-reduction. Using the radical pair formed during re-oxidation may represent a specific adaptation of the avian magnetic compass.

Specific Light-Emitting Diodes Can Suppress Sporulation of Podosphaera pannosa on Greenhouse Roses

When rose plants bearing colonies of Podosphaera pannosa were placed in a wind tunnel, the number of conidia trapped was directly proportional to intensity of daylight-balanced (white) light from 5 to 150 μmol m–2 s–1. Illumination of samples using blue (420 to 520 nm) light-emitting diodes (LEDs) increased the number of conidia trapped by a factor of approximately 2.7 over white light but germination of conidia under blue light was reduced by approximately 16.5% compared with conidia germination under white light. The number of conidia trapped under far-red (>685 nm) LEDs was approximately 4.7 times higher than in white light, and 13.3 times higher than under red (575 to 675 nm) LEDs, and germination was not induced compared with white light. When mildewed plants were exposed to cycles of 18 h of white light followed by 6 h of blue, red, far-red light, or darkness, light from the red LEDs reduced the number of conidia trapped by approximately 88% compared with darkness or far-red light. Interrupting the above dark period with 1 h of light from red LEDs also reduced the number of conidia trapped, while a 1-h period of light from far-red following the 1 h of light from red LEDs nullified the suppressive effect of red light. Our results indicate that brief exposure to red light during the dark interval may be as effective as continuous illumination in suppressing powdery mildew in greenhouse rose plant (Rosa × hybrida).

Watermelon seed germination. 2. Osmomanipulation of photosensitivity

Seed germination of watermelon (Citrullus lanatus cv. Sugar Baby) was fully suppressed by intermittent far-red (FR) irradiation (1 min every 30 min). When the intervening dark period was increased, a linearly increasing final germination percentage was obtained. However, a 4-day intermittent FR treatment induced phytochrome-controlled dormancy and the longer the dark interval the deeper was the dormancy of the non-germinated seeds. When seeds were soaked in a fully inhibitory osmotic solution, no dormancy was imposed. However, a single FR pulse at the time of transfer induced partial, secondary dormancy; the kinetics of the imposition of dormancy followed a negative exponential curve (half-life 1.5 days; 3 days for the cultivar Crimson Sweet). Seeds osmotreated for 10 days in darkness and subsequently dehydrated (with and without a final FR pulse) acquired germination characteristics similar to those in light-requiring and dark-germinating achenes, respectively, of the lettuce cultivar Grand Rapids. In the light-requiring osmomanipulated seed population, the induction of germination was brought about by the low-energy reaction of phytochrome, chilling, dry storage and decoating. The transformation through osmomanipulation of the dark-germinating watermelon seeds (the inhibition of which required prolonged exposure to light) to positively or negatively photosensitive seeds (that responded to brief light pulses), might be attributed to the slow relaxation of existing meta-Fa and meta-Rb phytochrome intermediates to Pfr upon hydration.

Effect of feeding on renin-angiotensin-aldosterone system of the horse

The effect of feeding frequency and associated meal size on the renin-angiotensin-aldosterone system (RAAS) in seven horses was examined. A daily maintenance ration of hay-grain pellets was provided either as a multiple feeding regimen (MF), in which the ration was divided into six equal portions fed at 4-h intervals, or as a single large feeding (SF) given from 9 A.M. until 11 A.M. Plasma renin activity (PRA), aldosterone (PAC), cortisol (PCC), protein concentration (TP), packed cell volume (PCV), and serum sodium and potassium were measured serially. To prevent significant RAAS stimulation due to strenuous exercise or by assuming orthostatism after a period of recumbency, the horses were trained to stand in 1 X 4-m tie stalls during the experiments. Changes in Na intake were prevented by disallowing nonration salt sources. A 12:12 light-dark interval was maintained. During the MF experiment, only serum Na changed diurnally, with concentrations lowest in early morning and highest before midday. In contrast, during the SF experiment, PRA was increased at 0.5, 1.0, and 3.0 h and PAC was increased at 3.0, 5.0, and 7.0 h after onset of feeding (P less than 0.005). Increased TP and PCV suggested transient hypovolemia was responsible for renin release. Significant increases in Na and decreases in K occurred while eating; however, K increased postprandially to be coincident with aldosterone. Except for a transient increase during feeding in SF, PCC demonstrated a similar circadian rhythm in both experiments. It was concluded that 1) episodic feeding (SF) causes significant diurnal variation of the RAAS in the horse, and 2) spontaneous circadian activity of the RAAS cannot be demonstrated in this species during a steady-state feeding regimen (MF).