scholarly journals Downy willow (Salix lapponum L.) as a component of different phytocoenoses in Polesie National Park

2012 ◽  
Vol 62 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Magdalena Pogorzelec
Keyword(s):  
Population Size ◽  
National Park ◽  
Habitat Conditions ◽  
Relict Species ◽  
Half Century ◽  
Wide Range ◽  
High Degree ◽  
Essential Problem ◽  
Salix Lapponum

The aim of this study was to make an evaluation of the current stands of a relict species, <i>Salix lapponum</i>, within the area of the Polesie National Park, to determine the population size and condition of downy willow as well as to analyse biocenotic conditions in its stands. The study, conducted in the years 2001-2003, allowed to establish that the number of <i>S. lapponum</i> stands had decreased significantly and that its population size in the confirmed stands in the Polesie National Park was substantially lower than 50 years ago. <i>Salix lapponum</i> was a component of different phytocoenoses, but its highest population size and a high degree of development were noted at the sites with the <i>Betulo-Salicetum</i> repentis and <i>Thelypteridi-Phragmitetum</i> communities. The character of the phytocoenoses in which <i>Salix lapponum</i> occurred in greatest numbers may evidence the wide range of tolerance of downy willow with respect to habitat conditions. There is a probability that not only the changes in its habitat conditions, which were noted over the last half-century, had a significant effect on the reduction in the number of stands and in the population size of this species. An essential problem appears to be the fact of the absence of flowering in individuals in many of the studied populations, which may result in an insufficient degree of adaptation of <i>S. lapponum</i> to changing habitat conditions.

Understanding Conformational Entropy in Small Molecules

2020 ◽  
Author(s):  
Lucian Chan ◽  
Garrett Morris ◽  
Geoffrey Hutchison
Keyword(s):  
Small Molecules ◽  
Degrees Of Freedom ◽  
Absolute Error ◽  
Low Energy ◽  
Standard Entropy ◽  
Free Energies ◽  
Conformational Entropy ◽  
Wide Range ◽  
High Degree ◽  
Empirical Corrections

The calculation of the entropy of flexible molecules can be challenging, since the number of possible conformers grows exponentially with molecule size and many low-energy conformers may be thermally accessible. Different methods have been proposed to approximate the contribution of conformational entropy to the molecular standard entropy, including performing thermochemistry calculations with all possible stable conformations, and developing empirical corrections from experimental data. We have performed conformer sampling on over 120,000 small molecules generating some 12 million conformers, to develop models to predict conformational entropy across a wide range of molecules. Using insight into the nature of conformational disorder, our cross-validated physically-motivated statistical model can outperform common machine learning and deep learning methods, with a mean absolute error ≈4.8 J/mol•K, or under 0.4 kcal/mol at 300 K. Beyond predicting molecular entropies and free energies, the model implies a high degree of correlation between torsions in most molecules, often as- sumed to be independent. While individual dihedral rotations may have low energetic barriers, the shape and chemical functionality of most molecules necessarily correlate their torsional degrees of freedom, and hence restrict the number of low-energy conformations immensely. Our simple models capture these correlations, and advance our understanding of small molecule conformational entropy.

Cerebellotrigeminal Dermal Dysplasia (Gómez-López-Hernández Syndrome)

2018 ◽  
Vol 16 (05) ◽  
pp. 362-368 ◽  
Author(s):  
Federica Sullo ◽  
Agata Polizzi ◽  
Stefano Catanzaro ◽  
Selene Mantegna ◽  
Francesco Lacarrubba ◽  
...  
Keyword(s):  
De Novo ◽  
Chromosomal Rearrangements ◽  
Number Of Patients ◽  
Wide Range ◽  
Visual Problems ◽  
Neurodevelopmental Abnormalities ◽  
Clinical Triad ◽  
High Degree ◽  
Motor Handicap

Cerebellotrigeminal dermal (CTD) dysplasia is a rare neurocutaneous disorder characterized by a triad of symptoms: bilateral parieto-occipital alopecia, facial anesthesia in the trigeminal area, and rhombencephalosynapsis (RES), confirmed by cranial magnetic resonance imaging. CTD dysplasia is also known as Gómez-López-Hernández syndrome. So far, only 35 cases have been described with varying symptomatology. The etiology remains unknown. Either spontaneous dominant mutations or de novo chromosomal rearrangements have been proposed as possible explanations. In addition to its clinical triad of RES, parietal alopecia, and trigeminal anesthesia, CTD dysplasia is associated with a wide range of phenotypic and neurodevelopmental abnormalities.Treatment is symptomatic and includes physical rehabilitation, special education, dental care, and ocular protection against self-induced corneal trauma that causes ulcers and, later, corneal opacification. The prognosis is correlated to the mental development, motor handicap, corneal–facial anesthesia, and visual problems. Follow-up on a large number of patients with CTD dysplasia has never been reported and experience is limited to few cases to date. High degree of suspicion in a child presenting with characteristic alopecia and RES has a great importance in diagnosis of this syndrome.

scholarly journals Controlling Teleportation-Based Locomotion in Virtual Reality with Hand Gestures: A Comparative Evaluation of Two-Handed and One-Handed Techniques

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 715
Author(s):  
Alexander Schäfer ◽  
Gerd Reis ◽  
Didier Stricker
Keyword(s):  
Virtual Reality ◽  
Virtual Worlds ◽  
User Preferences ◽  
Interaction Techniques ◽  
Hand Gestures ◽  
Wide Range ◽  
Effectiveness And Efficiency ◽  
High Degree ◽  
Additional Hardware ◽  
Comprehensive Study

Virtual Reality (VR) technology offers users the possibility to immerse and freely navigate through virtual worlds. An important component for achieving a high degree of immersion in VR is locomotion. Often discussed in the literature, a natural and effective way of controlling locomotion is still a general problem which needs to be solved. Recently, VR headset manufacturers have been integrating more sensors, allowing hand or eye tracking without any additional required equipment. This enables a wide range of application scenarios with natural freehand interaction techniques where no additional hardware is required. This paper focuses on techniques to control teleportation-based locomotion with hand gestures, where users are able to move around in VR using their hands only. With the help of a comprehensive study involving 21 participants, four different techniques are evaluated. The effectiveness and efficiency as well as user preferences of the presented techniques are determined. Two two-handed and two one-handed techniques are evaluated, revealing that it is possible to move comfortable and effectively through virtual worlds with a single hand only.

Krypton 85 myocardial blood flow: precordial scintillation versus coronary sinus sampling

1965 ◽  
Vol 209 (4) ◽  
pp. 705-710 ◽  
Author(s):  
Michael D. Klein ◽  
Lawrence S. Cohen ◽  
Richard Gorlin
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Coronary Sinus ◽  
Human Subjects ◽  
Radioactive Decay ◽  
Empirical Correction ◽  
Wide Range ◽  
Actual Flow ◽  
Flow Through ◽  
High Degree

Myocardial blood flow in human subjects was assessed by comparative simultaneous measurement of krypton 85 radioactive decay from coronary sinus and precordial scintillation. Empirical correction of postclearance background from precordial curves yielded a high degree of correlation between flows derived from the two sampling sites (r = .889, P < .001). Comparison of left and right coronary flows in nine subjects revealed similarity in flow through the two vessels over a wide range of actual flow values (r = .945, P < .001).

scholarly journals Ray Pahl's Sociological Career: Fifty Years of Impact

2011 ◽  
Vol 16 (3) ◽  
pp. 184-193 ◽  
Author(s):  
Graham Crow ◽  
Naoko Takeda
Keyword(s):  
Half Century ◽  
Wide Range ◽  
History Of ◽  
Current Concerns ◽  
British Sociology

The history of a discipline records the careers of its practitioners as well as providing an account their ideas. Studying these careers reveals much about the particular people and their work, and also provides insights into general questions such as how disciplines evolve, and how impact can be achieved amongst and beyond academic peers. This article focuses on the career of R. E. (Ray) Pahl. It argues that his position in British sociology over the last half century can be attributed in particular to two things. First, Pahl was committed to asking sociological questions whilst being open to other influences; we call him an interdisciplinary sociologist. Secondly, his approach engaged simultaneously with theoretical, methodological and substantive elements of the discipline rather than treating them as areas of separate expertise. These key facets of his work help in understanding why his work has reached such a wide range of audiences, and in explaining his distinctive record as a sociologist within and beyond the academy, which long pre-dates current concerns with ‘impact’.

Historical Dynamics

2018 ◽  
Author(s):  
Peter Turchin
Keyword(s):  
Religious Conversion ◽  
Synthetic Approach ◽  
Dynamical Processes ◽  
Factors Affecting ◽  
Historical Processes ◽  
Wide Range ◽  
Historical Dynamics ◽  
State Breakdown ◽  
Political Economic ◽  
High Degree

Many historical processes are dynamic. Populations grow and decline. Empires expand and collapse. Religions spread and wither. Natural scientists have made great strides in understanding dynamical processes in the physical and biological worlds using a synthetic approach that combines mathematical modeling with statistical analyses. Taking up the problem of territorial dynamics—why some polities at certain times expand and at other times contract—this book shows that a similar research program can advance our understanding of dynamical processes in history. The book develops hypotheses from a wide range of social, political, economic, and demographic factors: geopolitics, factors affecting collective solidarity, dynamics of ethnic assimilation/religious conversion, and the interaction between population dynamics and sociopolitical stability. It then translates these into a spectrum of mathematical models, investigates the dynamics predicted by the models, and contrasts model predictions with empirical patterns. The book's highly instructive empirical tests demonstrate that certain models predict empirical patterns with a very high degree of accuracy. For instance, one model accounts for the recurrent waves of state breakdown in medieval and early modern Europe. And historical data confirm that ethno-nationalist solidarity produces an aggressively expansive state under certain conditions (such as in locations where imperial frontiers coincide with religious divides). The strength of the book's results suggests that the synthetic approach advocated can significantly improve our understanding of historical dynamics.

Main approaches to treatment of hypoxia in acute respiratory distress syndrome, bacterial and viral pneumonia (part III)

2021 ◽  
pp. 38-55
Author(s):  
A. V. Vlasenko ◽  
E. A. Evdokimov ◽  
E. P. Rodionov
Keyword(s):  
Respiratory Failure ◽  
Distress Syndrome ◽  
Experimental Studies ◽  
Viral Pneumonia ◽  
Medical Technologies ◽  
Clinical Observations ◽  
Wide Range ◽  
Prevention And Treatment ◽  
High Degree

The paper summarizes data on modern approaches to the diagnosis, prevention and treatment of severe acute parenchymal respiratory failure of various origins, including ARDS due to bacterial viral pneumonia. The work is based on the data of modern well-organized studies, analysis of international clinical guidelines with a high degree of evidence, as well as the results of our own long-term experimental studies and clinical observations of the treatment of patients with ARDS of various origins, including viral pneumonia of 2009, 2016, 2020. Scientifically grounded algorithms for prevention, differential diagnosis and personalized therapy of severe acute respiratory failure using innovative medical technologies and a wide range of respiratory and adjuvant treatment methods have been formulated. The authors tried to adapt as much as possible the existing current recommendations for the daily clinical practice of anesthesiologists and resuscitators.

scholarly journals Large elastic deformations of isotropic materials. I. Fundamental concepts

1948 ◽  
Vol 240 (822) ◽  
pp. 459-490 ◽  
Keyword(s):  
The Body ◽  
Elastic Behaviour ◽  
Stress And Strain ◽  
Elastic Deformations ◽  
Hooke’S Law ◽  
Widespread Agreement ◽  
Wide Range ◽  
Hooke's Law ◽  
High Degree

The mathematical theory of small elastic deformations has been developed to a high degree of sophistication on certain fundamental assumptions regarding the stress-strain relationships which are obeyed by the materials considered. The relationships taken are, in effect, a generalization of Hooke’s law— ut tensio, sic vis . The justification for these assumptions lies in the widespread agreement of experiment with the predictions of the theory and in the interpretation of the elastic behaviour of the materials in terms of their known structure. The same factors have contributed to our appreciation of the limitations of these assumptions. The principal problems, which the theory seeks to solve, are the determination of the deformation which a body undergoes and the distribution of stresses in it, when certain forces are applied to it, and when certain points of the body are subjected to specified displacements. These problems are always dealt with on the assumption that the generalization of Hooke’s law is obeyed by the material of the body and that the deformation is small, i.e. the change of length, in any linear element in the material, is small compared with the length of the element in the undeformed state. Apart from the fact that the generalization of Hooke’s law is obeyed accurately by a very wide range of materials, under a considerable variety of stress and strain conditions, it has the further advantage that it leads to a mathematically tractable theory.

Content and Consistency in the Endogenous Depressive Pattern

1966 ◽  
Vol 112 (486) ◽  
pp. 471-484 ◽  
Author(s):  
Saul H. Rosenthal ◽  
Gerald L. Klerman
Keyword(s):  
19Th Century ◽  
The Other ◽  
Psychotic Depression ◽  
Public Attention ◽  
Half Century ◽  
Manic Depressive ◽  
Wide Range ◽  
The 19Th Century ◽  
Mourning And Melancholia ◽  
The Way

As currently used, the diagnosis of depression includes a wide range of clinical phenomena. This has not always been the case. Near the end of the 19th century, when the term depression began to evolve the meanings that it has today it was applied primarily to psychotics. The formulations of Freud in Mourning and Melancholia (1917), and of Kraepelin in Manic Depressive Insanity (1921) were based upon observations of patients who were both depressed and psychotic. In their work the contrast was between psychotic depression (or “melancholia”) on one hand, and normal sadness on the other. In the succeeding half-century, however, as psychiatry has extended its boundaries, increasing attention has been focused on non-psychotic depressions, often called “neurotic” or “reactive.” As these “neurotic” or “reactive” depressions reached public attention, a debate began over the way in which the depressive population should be described and the extent to which it should be subdivided. Critical and often sarcastic written battles were fought between the separatists and the unifiers during the 1920's and 1930's. These debates have been informatively chronicled by Partridge (1949). We have found it useful to divide these theorists into unifiers, dualists, and pluralists.

Sign in / Sign up

Export Citation Format

Share Document