Low Activity Conditions Research Articles

Fragmentation pathways of deprotonated ortho-hydroxybenzyl alcohol.

The ortho, meta, and para isomers of hydroxybenzyl alcohol can be unequivocally distinguished by the collision-induced dissociation mass spectra of their anions. The presence of a prominent peak at m/z 121 for an elimination of a dihydrogen molecule renders the ortho-isomer spectrum markedly different from those of its meta and para congeners. Investigations carried out with deuterium-labeled isotopologues of the ortho isomer verified that the labile hydrogen atom on the hydroxyl group and one of the benzylic hydrogen atoms are specifically removed in the formation of the m/z 121 ion. The ortho-isomer spectrum also showed a prominent peak at m/z 93. Experimental data indicated that the m/z 93 product ion originates either from a two-step H2and CO elimination mechanism or from a direct loss of a HCHO molecule from the precursor anion. The intensity ratio of the m/z 93 and 94 peaks in the spectrum recorded from the m/z 124 ion generated from a sample of o-hydroxybenzyl alcohol dissolved in D2O supported the notion that the direct HCHO loss is the more dominant pathway for the generation of the phenolate ion under low activation conditions. In contrast, the two-step mechanism becomes the more dominant pathway under high collisional activation conditions. The spectrum also showed a weak peak at m/z 105 for a water loss. Based on computational data, the m/z 105 ion generated in this way appears to be a composite generated from a common ion-neutral complex intermediate in which a hydroxyl anion is positioned equidistantly between one of the benzylic hydrogens and a nearby hydrogen atom of the benzene ring. Upon activation, the complex dissociates to form either a phenide or a quinone methide anion. The reaction forming a carbon dioxide adduct under ion-mobility conditions was used to support the proposed water-loss mechanism.

Electron precipitation characteristics during isolated, compound, and multi-night substorm events

Abstract. A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound substorms consist of multiple phase pairs, and multi-night substorm events refer to recurring substorm activity on consecutive nights. Approximately 200 nights of substorm activity observed over Fennoscandian Lapland have been analysed for their magnetic disturbance magnitude and the level of cosmic radio noise absorption. Substorm events were automatically detected from the local electrojet index data and visually categorized. We show that isolated substorms have limited lifetimes and spatial extents as compared to the other substorm types. The average intensity (both in absorption and ground-magnetic deflection) of compound and multi-night substorm events is similar. For multi-night substorm events, the first night is rarely associated with the strongest absorption. Instead, the high-energy electron population needed to cause the strongest absorption builds up over 1–2 additional nights of substorm activity. The non-linear relationship between the absorption and the magnetic deflection at high- and low-activity conditions is also discussed. We further collect in situ particle spectra for expansion and recovery phases to construct median precipitation fluxes at energies from 30 eV up to about 800 keV. In the expansion phases the bulk of the spectra show a local maximum flux in the range of a few keV to 10 keV, while in the recovery phases higher fluxes are seen in the range of tens of keV to hundreds of keV. These findings are discussed in the light of earlier observations of substorm precipitation and their atmospheric effects.

Details of the physiology of the aerodynamic and heat and moisture transfer in the normal nasal cavity

Anatomically accurate 3D models of 10 healthy nasal cavities are developed from computerized tomography (CT) scan images. Considering anatomical and physiological importance of different parts of the nasal cavity, the surface of each nasal passage is divided to eleven anatomical surfaces. Also the coronal cross sections in the nasal passage are divided to six sub-sections that share the total nasal passage airflow. The details of the flow field, heat transfer and water-vapor transport are numerically investigated for resting and low activity conditions. The mean and standard deviation of the different anatomical and air conditioning parameters such as: surface area, wall shear stress, heat and moisture transfer on different parts of the nasal passage surfaces and volume flow rates through different sections are presented. Results show that the percentages of airflow for inferior, middle and superior meatuses are 11.3 ± 6.4, 36.5 ± 9.5, 1.9 ± 0.81 % respectively and 4.1 ± 2.1 % of air passes through olfactory area. The inhaled air passing from the remaining surface (main passage) is 46.2 ± 10 %. Heat and moisture fluxes are highest in the anterior part of the nasal cavity, turbinates and lower part of the septum respectively. The percentage of the heat transfer from turbinates is 25.7 ± 3.9 % of total nasal heat transfer.

The effect of pro- and antioxidant processes on the formation of hypoandrogenism of adolescent boys

Оbjective — was toestablish the role of free radical oxidation and antioxidant defense processes in the development of hypoandrogenism(HA) in adolescent boys.Materials and methods. A total of 54 adolescent boys aged 13–18 years with HA were examined. The control group consisted of 84 boys of similar age with normal sexual and physical development. Determined the concentration of testosterone, indicators of free radical oxidation (FRO) and antioxidant defense (AOD). Statistical analysis of was performed using the Wilcoxon­Mann­Whitney test.Results and discussion. It has been established that testosterone level in adolescent boys with HA is several times less than in the control group, which confirms the presence of androgen deficiency in this cohort. In the examined patients, there were abnormalities in the ratio of processes FRO and AOD. A significant increase in reduced glutathione (RG) level, a decrease in the activity of catalase and glutathione peroxidase (GPO) were revealed. In half of the patients, the concentration of carbonylated proteins increases, while in a third, the concentration of TBA­active products increases. In adolescents with androgen deficiency in conditions of low activity of catalase and GPO, despite the high concentration of RG, neutralization of toxic products formed in the initial stages of FRO slows down, which leads to oxidative stressas shownby an increase of 1.5 times the coefficient of oxidative stress.Conclusions. The results indicate the formation of oxidative stress in boys with HA, the main initiator of which is the inhibition of the AOD system. The revealed features of changes in AOD parameters in adolescent boys allow pathogenetically substantiate the subsequent correction and prevention of antioxidant deficiency in the initial stages of HA, aimed at preventing the progression of this pathology.

Global Ionosphere Estimation Based on Data Fusion From Multisource: Multi‐GNSS, IRI Model, and Satellite Altimetry

AbstractTraditionally, the ionosphere determination just uses American Global Positioning System and Russian GLObal NAvigation Satellite System dual‐frequency data and has a low precision particularly on oceans. With the rapid development of Chinese BeiDou and European Galileo systems, they are playing an increasingly important role for modeling global ionosphere. Meanwhile, satellite altimetry provides valuable and precise ionosphere delay over the oceans. Through introducing priori ionosphere values from an advanced empirical ionosphere model, combining the advantages of Global Navigation Satellite System (GNSS) and satellite altimetry technologies, the precision of global ionosphere estimation can be further improved. To assess the improvement, we collect satellite altimetry data from Jason‐2/3 and more than 300 global GNSS stations, the data are processed in 2014 and 2018 when the Sun is in a high and a low activity conditions. The results suggest that the ionosphere determination based on multitechnique fusion in a solar‐geomagnetic reference frame is well suitable to represent the ionosphere and its structure. The determined ionosphere achieves a better global consistency, and its formal accuracy is significantly reduced. By comparing with the International GNSS Service products, evaluating by satellite altimetry measurements, and independently validating with ionosonde techniques, it is proved that the ionosphere results are further improved through employing additional available data, especially for the ionosphere over the oceans.

A molecular rheostat: Kv2.1 currents maintain or suppress repetitive firing in motoneurons.

Kv2 currents maintain and regulate motoneuron (MN) repetitive firing properties. Kv2.1 channel clustering properties are dynamic and respond to both high and low activity conditions. The enzyme calcineurin regulates Kv2.1 ion channel declustering. In patholophysiological conditions of high activity, Kv2.1 channels homeostatically reduce MN repetitive firing. Modulation of Kv2.1 channel kinetics and clustering allows these channels to act in a variable way across a spectrum of MN activity states. Kv2.1 channels are widely expressed in the central nervous system, including in spinal motoneurons (MNs) where they aggregate as distinct membrane clusters associated with highly regulated signalling ensembles at specific postsynaptic sites. Multiple roles for Kv2 channels have been proposed but the physiological role of Kv2.1 ion channels in mammalian spinal MNs is unknown. To determine the contribution of Kv2.1 channels to rat α-motoneuron activity, the Kv2 inhibitor stromatoxin was used to block Kv2 currents in whole-cell current clamp electrophysiological recordings in rat lumbar MNs. The results indicate that Kv2 currents permit shorter interspike intervals and higher repetitive firing rates, possibly by relieving Na+ channel inactivation, and thus contribute to maintenance of repetitive firing properties. We also demonstrate that Kv2.1 clustering properties in motoneurons are dynamic and respond to both high and low activity conditions. Furthermore, we show that the enzyme calcineurin regulates Kv2.1 ion channel clustering status. Finally, in a high activity state, Kv2.1 channels homeostatically reduce motoneuron repetitive firing. These results suggest that the activity-dependent regulation of Kv2.1 channel kinetics allows these channels to modulate repetitive firing properties across a spectrum of motoneuron activity states.

The Development of a Space Climatology: 3. Models of the Evolution of Distributions of Space Weather Variables With Timescale

AbstractWe study how the probability distribution functions of power input to the magnetosphere Pα and of the geomagnetic ap and Dst indices vary with averaging timescale, τ, between 3 hr and 1 year. From this we develop and present algorithms to empirically model the distributions for a given τ and a given annual mean value. We show that lognormal distributions work well for ap, but because of the spread of Dst for low activity conditions, the optimum formulation for Dst leads to distributions better described by something like the Weibull formulation. Annual means can be estimated using telescope observations of sunspots and modeling, and so this allows the distributions to be estimated at any given τ between 3 hr and 1 year for any of the past 400 years, which is another important step toward a useful space weather climatology. The algorithms apply to the core of the distributions and can be used to predict the occurrence rate of large events (in the top 5% of activity levels): they may contain some, albeit limited, information relevant to characterizing the much rarer superstorm events with extreme value statistics. The algorithm for the Dst index is the more complex one because, unlike ap, Dst can take on either sign and future improvements to it are suggested.

The role of neuronal activity in regulating metabolism in mouse and human astrocytes

BackgroundThe CNS has high energy requirements and CNS metabolism is often disrupted in disease. Astrocytes, the predominant CNS glucose utilisers, convert glucose to lactate to fuel neuronal metabolism. However, the extent to which this pathway is regulated by neuronal activity is poorly understood. We hypothesised that neuronal activity increases astrocytic metabolism, and have investigated the signalling underlying neuron–astrocyte metabolic crosstalk in mouse and human systems. MethodsPrimary mouse or human stem-cell derived astrocytes, expressing fluorescence-resonance energy transfer (FRET) biosensors for glucose or lactate, were co-cultured in vitro with primary cortical neurons. Neuronal activity was altered with 24 h of bicuculline (high activity) or tetrodotoxin (low activity). Glucose and lactate flux were determined by the rate of change of FRET ratio after inhibition of glucose uptake or lactate export. Transcriptomic analysis was done by RNA sequencing. FindingsNeuronal activity increased glucose metabolism in mouse astrocytes (rate of change in FRET ratio: bicuculline mean 1·58 per s [SD 0·17] vs tetrodotoxin 0·620 [0·20], p<0·0001) and human astrocytes (1·30 [0·32] vs 0·775 [0·19], p<0·0001). Neuronal activity also increased lactate production in mouse astrocytes (0·572 [0·38] vs 0·281 [0·21], p=0·028). Metabolic changes persisted after transfer from high to low activity conditions. Transcriptome analysis found activity-dependent upregulation of major components of the astrocyte–neuron lactate shuttle, with enrichment for the cAMP response element (CREB) promoter motif. CREB inhibition reversed activity-induced effects, and constitutively-active CREB was sufficient to increase astrocyte metabolism in low-activity conditions. InterpretationOur study found that neuronal activity, in mouse and human astrocytes, drove expression of metabolic genes and led to long-lasting enhancement of pathways for astrocyte–neuron metabolic support. These activity-dependent changes occured via activation of the CREB signalling pathway. These findings could have consequences for CNS metabolism when neuronal activity is reduced after neurodegeneration or iatrogenically during prolonged anaesthesia or sedation. FundingWellcome Trust.

Native MS Analysis of Bacteriorhodopsin and an Empty Nanodisc by Orthogonal Acceleration Time-of-Flight, Orbitrap and Ion Cyclotron Resonance.

Over the past two decades, orthogonal acceleration time-of-flight has been the de facto analyzer for solution and membrane-soluble protein native mass spectrometry (MS) studies; this however is gradually changing. Three MS instruments are compared, the Q-ToF, Orbitrap, and the FT-ICR, to analyze, under native instrument and buffer conditions, the seven-transmembrane helical protein bacteriorhodopsin-octylglucoside micelle and the empty nanodisc (MSP1D1-Nd) using both MS and tandem-MS modes of operation. Bacteriorhodopsin can be released from the octylglucoside-micelle efficiently on all three instruments (MS-mode), producing a narrow charge state distribution (z = 8+ to 10+) by either increasing the source lens or collision cell (or HCD) voltages. A lower center-of-mass collision energy (0.20-0.41 eV) is required for optimal bacteriorhodopsin liberation on the FT-ICR, in comparison to the Q-ToF and Orbitrap instruments (0.29-2.47 eV). The empty MSP1D1-Nd can be measured with relative ease on all three instruments, resulting in a highly complex spectrum of overlapping, polydisperse charge states. There is a measurable difference in MSP1D1-Nd charge state distribution (z = 15+ to 26+), average molecular weight (141.7 to 169.6 kDa), and phospholipid incorporation number (143 to 184) under low activation conditions. Utilizing tandem-MS, bacteriorhodopsin can be effectively liberated from the octylglucoside-micelle by collisional (Q-ToF and FT-ICR) or continuous IRMPD activation (FT-ICR). MSP1D1-Nd spectral complexity can also be significantly reduced by tandem-MS (Q-ToF and FT-ICR) followed by mild collisional or continuous IRMPD activation, resulting in a spectrum in which the charge state and phospholipid incorporation levels can easily be determined.

MENINGKATKAN AKTIVITAS HASIL BELAJAR SISWA DALAM PEMBELAJARAN PKn PADA MATERI HAK ASASI MANUSIA (HAM) DENGAN MENGGUNAKAN MODEL JIGSAW DI KELAS X4 SMA NEGARI 10 BANJARMASIN

Dini Maylinda Kusumawati, 2013. Improving Student Learning Outcomes Activities In PKN Learning Materials for Human Rights (HAM) Using Model Jigsaw Classroom Exp X4 Negari 10 Banjarmasin. Supervisor (I) H. Sarbaini (II) Mariatul Kiptiah . The learning process in the classroom X4 Civics SMAN 10 Banjarmasin tend not achieve the expected results . Conditions of low activity affects the quality of student learning in the classroom . Learning that takes place in a class of students who are good looks alone were active when expressed opinion, this situation results in students who are still not familiar with the material described teachers feel embarrassed to ask and express their opinions because they feel unappreciated . Lack of democratic attitudes of students can be seen from the low motivation of democracy students in the group discussions . Students pay less attention to the teacher explaining and self-absorbed , only a few students were able to catch the teacher explained the material . This resulted in poor learning outcomes . The purpose of the study was : (1) To determine the activity of teachers in applying the Jigsaw learning model class X4 human rights materials SMAN 10 Banjarmasin (2) To raise the students in learning activities through the application of human rights materials Civics learning model SMAN 10 Jigsaw X4 class Banjarmasin (3) To improve learning outcomes of students in the subject matter of human rights in Civics class X4 SMAN 10 Banjarmasin . Data collection techniques used in action research (PTK) is the observation , documentation and test results of study conducted through several cycles , the first cycle and second cycle . The results of this study indicate (1) Teaching teachers to implement learning models Jigsaw takes place smoothly. In the first cycle of learning in teacher qualifications good enough and the second cycle has increased very well with good qualifications.(2) Activities of students has increased very well with good qualifications.(3) The learning process is applying the Jigsaw model can increase the activity of students and student learning outcomes . Based on these results, it is suggested that the school can determine langah and school policies towards better learning improvement. Civics teacher, should mengtadakan renewal in the learning process, especially the Jigsaw model, so as to achieve optimal learning implementation. Keywords: Activity, learning outcomes Civics, Jigsaw

Total Design of Active Neck Support System for Economy Class Aircraft Seat

Travel by air with long hours will create discomfort feeling for aircraft passenger especially economy class aircraft passenger. Long hour air travel will create physiological stress on aircraft passenger. It may due to seat space limitation, noise, vibration, cabin humidity as well as seat comfort. Seat comfort is a subjective feeling that related to psychological aspect of aircraft passenger. The current aircraft passenger seat is equipped with a passive function where the passenger themselves needs to adjust the seat for comfort seating position. The aircraft passenger will not able to adjust the seat when the aircraft passenger is in the low activity condition. The active seat support system was developed to support the aircraft passenger actively. The first prototype of active seat support system is focus on neck section. The head position of the aircraft seat was embedded with the system to detect the head position of the passenger. During the development of the active seat support system, total design technique was used. Five conceptual designs were generated for selection. To determine the final design of active neck support system, the matrix evaluation method was used. The weight of the concept was obtained through weight analysis.

Identity of endogenous NMDAR glycine site agonist in amygdala is determined by synaptic activity level

Mechanisms of NMDA receptor-dependent synaptic plasticity contribute to the acquisition and retention of conditioned fear memory. However, synaptic rules which may determine the extent of NMDA receptor activation in the amygdala, a key structure implicated in fear learning, remain unknown. Here we show that the identity of the NMDAR glycine site agonist at synapses in the lateral nucleus of the amygdala may depend on the level of synaptic activation. Tonic activation of NMDARs at synapses in the amygdala under low-activity conditions is supported by ambient D-serine, whereas glycine may be released from astrocytes in response to afferent impulses. The release of glycine may decode the increases in afferent activity levels into enhanced NMDAR-mediated synaptic events, serving an essential function in the induction of NMDAR-dependent long-term potentiation in fear conditioning pathways.

Temporal dynamics of a homeostatic pathway controlling neural network activity

Neurons use a variety of mechanisms to homeostatically regulate neural network activity in order to maintain firing in a bounded range. One such process involves the bi-directional modulation of excitatory synaptic drive in response to chronic changes in network activity. Down-scaling of excitatory synapses in response to high activity requires Arc-dependent endocytosis of glutamate receptors. However, the temporal dynamics and signaling pathways regulating Arc during homeostatic plasticity are not well understood. Here we determine the relative contribution of transcriptional and translational control in the regulation of Arc, the signaling pathways responsible for the activity-dependent production of Arc, and the time course of these signaling events as they relate to the homeostatic adjustment of network activity in hippocampal neurons. We find that an ERK1/2-dependent transcriptional pathway active within 1–2 h of up-regulated network activity induces Arc leading to a restoration of network spiking rates within 12 h. Under basal and low activity conditions, specialized mechanisms are in place to rapidly degrade Arc mRNA and protein such that they have half-lives of less than 1 h. In addition, we find that while mTOR signaling is regulated by network activity on a similar time scale, mTOR-dependent translational control is not a major regulator of Arc production or degradation suggesting that the signaling pathways underlying homeostatic plasticity are distinct from those mediating synapse-specific forms of synaptic depression.

Simulation of airflow and aerosol deposition in the nasal cavity of a 5-year-old child

As a human grows from birth to adulthood, both airway anatomy and breathing conditions vary that alter the deposition rate and pattern of inhaled aerosols. However, deposition studies have typically focused on adult subjects, results of which may not be readily extrapolated to children. Furthermore, because of greater ventilation rate per body weight, children receive a greater dose than adults and therefore are more susceptible to respiratory risks. This study is to evaluate the transport and deposition of respiratory aerosols in a nasal-laryngeal airway model based on MRI head images of a 5-year-old boy. Differences between this child and adults in nasal physiology and aerosol filtering efficiency will be emphasized. A validated low Reynolds number (LRN) k− ω turbulence model was employed to simulate laminar, transitional, and fully turbulent flow regimes within the nasal airways. Particle trajectories and deposition in the spectrum of 0.5–32 μm were evaluated using a well-tested Lagrangian tracking approach for inhalation flow rates ranging from sedentary (3 L/min) to heavily active (30 L/min) conditions. Simulation results of the inhalation pressure drop and particle deposition rate provided a reasonable match with existing experimental results in nasal airway casts of children. Much higher breathing resistance was observed in the 5-year-old child compared to adults. Furthermore, deposition patterns were sensitive to inhalation flow rate under low activity conditions. An empirical correlation of child nasal filtering efficiency was proposed for micrometer particles based on a wide range of test conditions. Results of this study demonstrate that significant child–adult difference exists in inhaled aerosol depositions, which should be taken into account for risk assessment of airborne toxicants on infants and children.

Validity of the two-node model for predicting steady-state skin temperature

The validity of the two-node model for predicting the skin temperature in the thermal steady state is studied by comparing the calculated and experimental results for various thermal conditions. For the experimental results of steady-state skin temperature, in addition to the authors’ original experimental data, literature data for mean skin temperature are collected, incorporating 56 conditions and 233 subjects in total. The results show that the two-node model (the 1986 edition) that is widely used for calculating SET* predicts effectively the steady-state skin temperature in the low-activity conditions. Additionally, the changes that were made to the two-node model by Gagge et al. and ASHRAE are summarized. It is shown theoretically and by experimental validations that, of these changes, the addition of the shivering model represents the most significant improvement in terms of predicting the skin temperature in the steady state.

Re-evaluation of Stolwijk's 25-node human thermal model under thermal-transient conditions: Prediction of skin temperature in low-activity conditions

The performance of Stolwijk's 25-node thermal model of the human body was evaluated for the prediction of the skin temperature of a sedentary person in a thermal-transient state. The skin temperature calculated by the original Stolwijk model was compared to experimental data obtained systematically from a large number of subjects exposed to stepwise changes in environmental conditions, including neutral (29.4 °C), low (19.5 °C), and high (38.9 °C) ambient temperatures. The results show that the original Stolwijk model accurately predicts both the absolute value and the tendency in the transient mean skin temperature. This suggests that the Stolwijk model is valid for the prediction of the transient mean skin temperature for the “average” person under low-activity conditions. Discrepancies are observed in the local skin temperature for some segments. However, these discrepancies can be significantly reduced through modification of the basal skin blood flow distributions and the distributions of vasoconstriction and workload in the model.

Improved quantification of Dehalococcoides species by fluorescence in situ hybridization and catalyzed reporter deposition

Chlorinated ethenes contamination of soil and groundwater is a widespread problem in most industrialized countries. To date, there is a general consensus in the literature that members of the genus Dehalococcoides are required for complete dechlorination of these compounds. The availability of specific identification tools to track their distribution in the field is therefore a topic of particular relevance in environmental studies. These microorganisms have been successfully visualized by fluorescence in situ hybridization (FISH) in highly active dechlorinating cultures. However, FISH detection of Dehalococcoides under low activity conditions can be strongly hampered by their small cell size and low ribosome content. In this study, catalyzed reporter deposition (CARD)-FISH was employed as an alternative detection method. In a trichloroethene (TCE) dechlorinating enrichment culture, CARD-FISH, using proteinase K as a permeabilization pre-treatment, was found to be significantly superior to conventional FISH in terms of both microscopic visualization and quantification efficiency (about 30%). An application of this method on contaminated aquifer samples is also presented and discussed.

Application of a rapid direct viable count method to deep-sea sediment bacteria

For the first time, a Live/Dead® (L/D) Bacterial Viability Kit (BacLight™) protocol was adapted to marine sediments and applied to deep-sea sediment samples to assess the viability (based on membrane integrity) of benthic bacterial communities. Following a transect of nine stations in the Fram Strait (Arctic Ocean), we observed a decrease of both bacterial viability and abundance with increasing water (1250–5600 m) and sediment depth (0–5 cm). Percentage of viable (and thus potentially active) cells ranged between 20–60% within the first and 10–40% within the fifth centimetre of sediment throughout the transect, esterase activity estimations (FDA) similarly varied from highest (13.3±5.4 nmol cm −3 h −1) to lowest values below detection limit down the sediment column. Allowing for different bottom depths and vertical sediment sections, bacterial viability was significantly correlated with FDA estimations ( p<0.001), indicating that viability assessed by BacLight staining is a good indicator for bacterial activity in deep-sea sediments. Comparisons between total L/D and DAPI counts not only indicated a complete bacterial cell coverage, but a better ability of BacLight staining to detect cells under low activity conditions. Time course experiments confirmed the need of a rapid method for viability measurements of deep-sea sediment bacteria, since changes in pressure and temperature conditions caused a decrease in bacterial viability of up to 50% within the first 48 h after sample retrieval. The Bacterial Viability Kit proved to be easy to handle and to provide rapid and reliable information. It's application to deep-sea samples in absence of pressure-retaining gears is very promising, as short staining exposure time is assumed to lessen profound adverse effects on bacterial metabolism due to decompression.

Time-Dependent 2D Model Compared with Observations during the 1974 Mini Cycle

The 1974 mini-cycle is a medium term cosmic ray modulation event with about one year duration. It occurred in an A > 0 epoch of solar magnetic polarity during conditions of low activity, but with an increase in the latitudinal extent of the heliospheric current sheet (tilt angle α) and the magnitude B of the heliospheric magnetic field. This cosmic ray decrease can be used to test the hypothesis that such large scale decreases (mini cycles) may be caused primarily by a combination of changes in α and B. For this purpose a fully time-dependent 2D model of solar modulation is used, which includes the effects of global and current sheet drifts, and anisotropic perpendicular diffusion. Such models have been used successfully to describe the proton energy spectrum as well as the radial and latitudinal gradients near I AU. Comparison of the model solutions with the observed decrease for 1.8 GV protons allows us to study the combined influence of variable drift and diffusion effects throughout the event.

Effects of increased lifespan on chromatin condensation in the adult male housefly

Analysis of the chromatin condensation pattern in optic lobe nuclei from the adult male housefly has shown significant differences in males from a long lived, low activity (LA) group as compared to a short lived, high activity (HA) group. The rate of chromatin condensation in the LA group was very much less than that observed in the HA group, leaving the nuclei from the former group in a permanently lowered condensation state. Moreover, a detailed comparison of the amount and spatial distribution of a single high density chromatin component (HDC) suggests that the low activity conditions not only lowers the rate of chromatin condensation but also alters the normal program controlling this process. Linear discriminant analysis showed that a consistently higher percentage of nuclei from the LA group, as compared to the HA group, could be classified with a 1-day-old model derived from the HA group. These results are discussed with respect to environmental influences on lifespan and are compared to the response of lipofuscin accumulation in low activity male houseflies.