The Gravity Between Us Epub
Vinnie Breidenthal
Understanding the effects of increased and decreased gravity on central nervous system is essential for developing proper physical and cognitive countermeasures to assure safe and effective space missions and human survival in space. This short review covers the available literature on the brain electrocortical activity effects of decreased and increased gravitational force comparing to the 1g Earth conditions. Among all neuroimaging methods such as functional magnetic resonance imaging (fMRI), positron-emission tomography (PET), diffusion tensor imaging (DTI), the electroencephalography (EEG) was found to be suitable method to monitor brain electrocortical activity in the extreme environments. Due to complexity and high cost of space flight missions, ground-based models have been employed to simulate microgravity effects on human body. Surprisingly, there is very limited number of publications reporting gravity-dependent EEG spectral changes. With increased gravity there are initially increased EEG activity in higher frequencies and at around 4 g appears loss of consciousness with accompanying slowing of EEG due to hypoxia. In microgravity, the most prevalent changes in EEG are faster frequencies such as alpha and beta. The results from simulated microgravity (bed rest) are pointing to changes in theta and alpha, representing signs of cortical inhibition. The changes in EEG activity in space flight are attributed to a decreased sensorimotor input while in parabolic flights short and fast transitions from hyper to microgravity presumably reflect lower arousal levels and emotional processes in microgravity. Thus, based on limited research about gravity-related changes in EEG from different environments it is difficult to draw any unequivocal conclusions. Additional systematic studies about electrocortical activity in space and parabolic flights, as well as longer bed rest studies are needed in order to advance knowledge about brain functioning in extreme conditions such as space flights.
Reduced gravity offers unique opportunities to study motor behavior. This paper aims at providing a review on current issues of the known tools and techniques used for hypogravity simulation and their effects on human locomotion. Walking and running rely on the limb oscillatory mechanics, and one way to change its dynamic properties is to modify the level of gravity. Gravity has a strong effect on the optimal rate of limb oscillations, optimal walking speed, and muscle activity patterns, and gait transitions occur smoothly and at slower speeds at lower gravity levels. Altered center of mass movements and interplay between stance and swing leg dynamics may challenge new forms of locomotion in a heterogravity environment. Furthermore, observations in the lack of gravity effects help to reveal the intrinsic properties of locomotor pattern generators and make evident facilitation of nonvoluntary limb stepping. In view of that, space neurosciences research has participated in the development of new technologies that can be used as an effective tool for gait rehabilitation.
Background: Specific gravity (SG) may perform as well as creatinine (CR) correction for adjusting urinary hormone concentrations, as well as offer some advantages. We compared the two methods and applied them to US and Bangladeshi specimens to evaluate their use in different populations.
Methods: Pearson correlations between serum concentrations and SG, CR, and uncorrected urinary concentrations were compared using paired daily urine and serum specimens from one menstrual cycle from 30 US women. Corrected urinary estrone conjugate and pregnanediol glucuronide concentrations were compared with serum estradiol and progesterone. Urine specimens across one menstrual cycle from 13 Bangladeshi women were used to evaluate the applicability of both methods to a nonindustrialized population. Linear mixed-effects models were used to compare CR and SG values in the Bangladeshi vs US specimens.
Results: There was no significant difference between SG-corrected vs serum and CR-corrected vs serum correlations for either assay. Usable CR results were obtained for all US specimens, but 37% of the Bangladeshi specimens were below the CR assay limit of detection. The Bangladeshi sample had significantly lower CR and higher inter- and intrasubject CR variability than the US sample.
Creation reflects God by its beauty and harmony, but, through the evil and death which abide in it and the blind necessity by which it is governed, it also reflects the absence of God. We have issued from God: that means that we bear his imprint and it means also that we are separated from him. The etymology of the word to exist (to be placed outside) is very illuminating in this respect: we can say we exist, we cannot say we are. God who is Being has in a sense effaced himself so that we can exist: he has given up being everything in order that we might exist; he has dispossessed himself in our favour of his own necessity, which is identical with goodness, to allow another necessity to reign which is alien and indifferent to good. The central law of this world, from which God has withdrawn by his very act of creation, is the law of gravity, which is to be found analogously in every stage of existence. Gravity is the force which above all others draws us from God. It impels each creature to seek everything which can preserve or enlarge it and, as Thucydides says, to exercise all the power of which it is capable. Psychologically it is shown by all those motives which are directed towards asserting or reinstating the self, by all those secret subterfuges (lies of the inner life, escape in dreams or false ideals, imaginary encroachments on the past and the future, etc.) which we make use of to bolster up from inside our tottering existence, that is to say, to remain apart from and opposed to God.
All the writings contained in this book have been taken from the manuscripts which Simone Weil confided to me personally. They were therefore all written before May 1942. More recent work, which her parents have been kind enough to show me, has not been included here. I have myself chosen the extracts from the notebooks, in which they were interspersed with innumerable quotations as well as philological and scientific studies. I hesitated between two ways of presentation: either to give the thoughts of Simone Weil one after the other in the order of their composition, or to classify them. The second method seemed preferable. I am anxious to express my thanks to all who have helped and encouraged me in this work: the Reverend Father Perrin, Lanza del Vasto, M. and Mme Honnorat (who were personal friends of Simone Weil), Gabriel Marcel and Jean de Fabrèques. In the checking and transcription of the texts M. V.-H. Debidour, who kindly helped to translate the Greek quotations incorporated in the aphorisms, and my devoted colleague Mlle Odile Keller have both given an infinite amount of valuable help.
Gravity. Generally what we expect of others depends on the effect of gravity upon ourselves, what we receive from them depends on the effect of gravity upon them. Sometimes (by chance) the two coincide, often they do not.
When in this state, I have several times succumbed to the temptation at least to say words which cause pain. Obedience to the force of gravity. The greatest sin. Thus we corrupt the function of language, which is to express the relationship between things.
Attachment is no more nor less than an insufficiency in our sense of reality. We are attached to the possession of a thing because we think that if we cease to possess it, it will cease to exist. A great many people do not feel with their whole soul that there is all the difference in the world between the destruction of a town and their own irremediable exile from that town.
I must withdraw so that God may make contact with the beings whom chance places in my path and whom he loves. It is tactless for me to be there. It is as though I were placed between two lovers or two friends. I am not the maiden who awaits her betrothed, but the unwelcome third who is with two betrothed lovers and ought to go away so that they can really be together.
To be only an intermediary between the uncultivated ground and the ploughed field, between the data of a problem and the solution, between the blank page and the poem, between the starving beggar and the beggar who has been fed.
Obedience. There are two kinds. We can obey the force of gravity or we can obey the relationship of things. In the first case we do what we are driven to by the imagination which fills up empty spaces. We can affix a variety of labels to it, often with a show of truth, including righteousness and God. if we suspend the filling up activity of the imagination and fix our attention on the relationship of things, a necessity becomes apparent which we cannot help obeying. Until then we have not any notion of necessity and we have no sense of obedience.
There is an essential difference between the mysticism which turns towards God the faculty of love and desire of which sexual energy constitutes the physiological foundation, and the false imitation of mysticism which, without changing the natural orientation of this faculty, gives it an imaginary object upon which it stamps the name of God as a label. To discriminate between these two operations, of which the second is still lower than debauchery, is difficult, but it is possible.
Do not allow yourself to be imprisoned by any affection. Keep your solitude. The day, if it ever comes, when you are given true affection there will be no opposition between interior solitude and friendship, quite the reverse. It is even by this infallible sign that you will recognize it. Other affections have to be severely disciplined.
To transfer evil to what is exterior is to distort the relationship between things. That which is exact and fixed, number, proportion, harmony, withstands this distortion. Whatever my state, whether vigorous or exhausted, in three miles there are three milestones. That is why number hurts when we are suffering: it interferes with the operation of transference. To fix my attention on what is too rigid to be distorted by my interior modifications is to prepare to make possible within myself the apparition of something changeless and an access to the eternal.
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