Leaf-specific Farquhar-von Caemmerer-Berry (FvCB) model was fitted to characterize the vertical profile of photosynthetic CO2 response within rice canopy. Leaf-position-specific and canopy average FvCB models were fitted to study a suitable leaf representing photosynthetic parameters at the canopy scale. The results showed that leaf photosynthesis was limited by Rubisco activity or ribulose-1,5-bisphosphate regeneration under field conditions. The maximum rate of carboxylation, maximum rate of electron transport, rate of triose phosphates utilization, and light respiration rate in the FvCB model reached the highest values for the top second leaf and then decreased, while the mesophyll diffusion conductance kept decreased in downward leaves. The integrated photosynthetic CO2-response curves for the top fourth and fifth leaves were appropriate for estimating parameters in the FvCB model at the canopy scale.
Intense collisional transport of bimodal sediment mixture in open-channel turbulent flow with water as carrying liquid is studied. The study focusses on steep inclined flows transporting solids of spherical shape and differing in either size or mass. A process of vertical sorting (segregation) of the two different solids fractions during the transport is analyzed and modelled. A segregation model is presented which is based on the kinetic theory of granular flows and builds on the Larcher-Jenkins segregation model for dry bimodal mixtures. Main modifications of the original model are the carrying medium (water instead of air) and a presence of a non-uniform distribution of sediment across the flow depth. Testing of the modified model reveals that the model is applicable to flow inclination slopes from 20 to 30 degrees approximately, making it appropriate for debris flow conditions. Changing the slope outside the specified range leads to numerical instability of the solution. A use of the bimodal mixture model is restricted to the grain size ratio 1.4 and no restriction is found for the grain mass ratio in a realistic range applicable to natural conditions. The model reveals trends in the vertical sorting under variable conditions showing that the sorting is more intense if flow is steeper and/or the difference in size or mass is bigger between the two sediment fractions in a bimodal mixture.
Schizophrenia has a debilitating impact on patient,s cognitive functioning and everyday activities. As a part of the treatment, schizophrenia patients attend sessions of cognitive remediation to restore impaired cognitive abilities. To combine cognitive and real life training, this study presents a virtual task to use in cognitive rehabilitation and assessment. Virtual Supermarket Shopping Task (VSST) simulates a shopping activity, in which participants have to memorize and collect items from a virtual supermarket. The aim of this study is to establish its validity for use in clinical practice.Sample and setting. Twenty patients suffering from chronic schizophrenia and twenty healthy controls were tested. Each participant complet-ed the task and a battery of standard neuropsy-chological tests.Statistical analyses. Groups’ results were com-pared by Student’s t-tests., Validity of VSST was examined using correlations with standard neu-ropsychological measures. Several VSST met-rics, such as trial difficulty, distances and times, and the effect the extraneous variables have on VSST measures were investigated using analyses of variance and mixed effect models. The analyses demonstrate that patients perform worse in VSST than healthy controls and their performance corresponds to their mnemonic abilities measured by standard neuropsy-chological tests. VSST performance relates to the level of executive functioning only in patients. There was no effect of gaming experience on VSST performance. While potential gender effect has to be addressed in future studies, age seems to play a role in the additional VSST measures (trial time and distance).Study limitations. Subjects were tested only once and therefore long term benefits of using VSST in rehabilitation could not be investigated. Only schizophrenia patients were included in the sample, which reduces generalizability of results to other psychiatric and neurologic conditions., Schizofrenie je onemocnění výrazně omezující kognitivní schopnosti člověka a jeho každodenní fungování. Pacienti se schizofrenií v rámci léčby podstupují kognitivní remediaci za účelem zlepšení svých kognitivních schop-ností. Virtuální úloha určená ke kognitivní re-habilitaci a vyšetření kognitivních funkcí byla vytvořena s cílem propojení kognitivního tréninku s tréninkem v reálných životních pod-mínkách. Úloha nákupu ve virtuálním supermarketu (ÚNVS) simuluje proces nákupu, při kterém si jedinec musí zapamatovat a posbírat produkty ve virtuálním supermarketu. Cílem této studie je stanovit validitu úlohy pro její využití v klinické praxi. Soubor a procedura. V rámci studie bylo otestováno dvacet pacientů trpících chronickou schizo-frenií a dvacet zdravých dobrovolníků. Každý respondent absolvoval úlohu společně s baterií standardních neuropsychologických testů.Statistická analýza. Výsledky skupin byly porovnány pomocí t-testu. Validita ÚNVS byla stanovena na základě Pearsonovy korelace se standardními neuropsychologickými testy. Pomocí lineární regrese a lineárních smíšených modelů byly podrobně prozkoumány jednotlivé proměnné, jako je obtížnost úlohy, ušlá vzdálenost či čas. Ověřen byl i vliv vnějších proměnných na výsledky v testu., and Analýza prokázala, že výkon SZ pacientů v ÚNVS je horší oproti výkonu zdravých dobrovolníků a tento výkon odpovídá úrovni jejich paměťových schopností zachycené standardními neuropsychologickými testy. Pouze ve skupině SZ pacientů byl zjištěn vztah mezi výkonem v ÚNVS a exekutivními funkcemi. Ana-lýza neodhalila žádný efekt zkušenosti s hraním počítačových her na výkon v ÚNVS. Zatímco efekt pohlaví musí být ověřen v následujících studiích, výsledky studie naznačují, že věk respondenta může mít vliv na vybrané proměnné ÚNVS (ušlá vzdálenost a čas řešení úlohy).Omezení studie. Participanti absolvovali úlohu pouze jednou, a proto nemohl být ověřen dlouhodobý přínos ÚNVS v rehabilitaci. Výzkumný soubor byl tvořen pouze pacienty se schizofrenií, což omezuje možnost zobecnění výsledků na jiná psychiatrická a neurologická onemocnění.
Based on the fact that tremors display some distinct 3D spatial
characteristics, we decided to visualize tremor planes in 3D
space. We obtained 3-axial linear accelerometer signals of hand
tremors from 58 patients with Parkinson´s disease (PD), 37 with
isolated resting tremor (iRT), 75 with essential tremor (ET), and
44 healthy volunteers with physiological tremor (Ph). For each
group analysis was done with subsequent spatial 3D regression
of the input data i.e. along the x, y and z axes; the projected
vector lengths in the individual (vertical transversal XY, vertical
longitudinal XZ and horizontal YZ) reference frame planes and
their angles. Most meaningful and statistically significant
differences were found in the analyses of the 3D vector lengths.
The tremor of the PD and the iRT group was oriented mainly in
the horizontal YZ plane. The tremors of the patients with ET and
Ph were oriented approximately in the midway between the all
three referential planes with less tilt toward the vertical
longitudinal XZ plane.
Polyhydroxylated derivatives of 6-keto,7-dehydrocholesterol (ecdysteroids) are common constituents of various plants.
In 1965, they were accidentally discovered in the search for the insect moulting hormone. These biologically important natural
compounds are neither insect hormones nor inducers of insect ecdysis. Due to their strong anabolic, vitamin D-like effects in insects, domestic animals and humans, I propose the use of the arbitrary term vitamin D1
. The present paper describes the effects
of vitamin D1
on the growth and regeneration of excised epidermal cells of the tobacco hornworm, Manduca sexta (Sphingidae).
The periods of programmed cell death and cell proliferation (histolysis and histogenesis, respectively) exactly coincide in insects
with endogenous peaks of increased concentration of vitamin D1
. Epidermal cells communicate with each other, creating a mutually integrated tissue, connected by mechanical, chemical, electrical, ionic or other so far incompletely known factors. After natural
cell death, or after the artifi cial removal of some epidermal cells, the neighbouring cells that lose communication integrity, begin
to divide mitotically to replace the disconnected part. Cell divisions are arrested as soon as the integrity of the living tissue is
established. During insect ontogeny, the application of juvenile hormone causes regenerating epidermal cells to repeat the previous morphogenetic programme (i.e., development of patches of larval tissue on the body of a pupa, or metathetely). Conversely,
the application of vitamin D1
(20-hydroxyecdysone) caused the regenerating cells to prematurely execute a future morphogenetic
programme (i.e., development of patches of pupal tissue on the body of a larva, or prothetely). Among the key features of insect
regeneration, is the arrest of cell divisions when tissues resume living cell-to-cell integrity. This prevents the formation of aberrant groups of cells, or tumours. It is well established that the main physiological systems of insects (e.g., circulatory, respiratory,
neuro-endocrine) are structurally and functionally similar to corresponding systems in humans. Thus the basic principles of cell
regeneration and the role of vitamin D1
in insects may also be valid for humans. The common vitamins D2
(ergocalciferol) or D3
(cholecalciferol), are exclusively lipid soluble secosterols, which require activation by UV irradiation and hydroxylation in the liver.
By contrast, the neglected vitamin D1
is a natural derivative of polyhydroxylated 7-dehydrocholesterol of predominantly plant origin, which is both partly a water and partly a lipid soluble vitamin. It neither requires UV irradiation, nor hydroxylation due to 6 or
7 already built-in hydroxylic groups. Like other vitamins, it enters insect or human bodies in plant food or is produced by intestinal
symbionts. Vitamin D1
causes strong anabolic, vitamin D-like effects in domestic animals and in humans. I am convinced that
avitaminosis associated with a defi ciency of vitamin D1 in human blood may be responsible for certain hitherto incurable human
diseases, especially those related to impaired nerve functions and somatic growth, aberrant cell regeneration or formation of
malignant tumours.
Vitamin D3 is well-known as a major regulator of calcium and
phosphorus homeostasis. A growing body of evidence highlights
its crucial role in the regulation of reproductive processes in
females. The role of vitamin D3 in the female reproductive tract
has been extensively investigated because its receptor is
abundant in reproductive organs, including ovary. Importantly,
besides expression of vitamin D3 receptor, the ovary is an
extrarenal site of vitamin D3 metabolism. The influence of vitamin
D3 on follicular development and ovarian steroidogenesis has
been investigated. Furthermore, vitamin D3 deficiency has also
been associated with polycystic ovary syndrome, premature
ovarian failure and ovarian cancer. The objective of this review is
to summarize our knowledge about the contribution of vitamin D3
to physiological and pathological processes within the ovary.