194 research outputs found
Adult demography of an isolated population of the threatened butterfly Scarce Heath Coenonympha hero and its conservation implications
Input-output linearization and decoupling of mechanical control systems
In this work, we present a problem of simultaneous input-output feedback
linearization and decoupling (non-interacting) for mechanical control systems
with outputs. We show that the natural requirement of preserving mechanical
structure of the system and of transformations imposes supplementary conditions
when compared to the classical solution of the same problem for general control
systems. These conditions can be expressed using objects on the configuration
space only. We illustrate our results with several examples of mechanical
control systems
THE BEHAVIOURAL REACTION OF WEANERS TO HANGING TOYS: WOODEN BALL AND AROMATIZED WOODEN BALL – WAY TO REDUCE AGGRESSION AFTER MIXING
The behaviour of weaners after mixing housed in pens equipped with hanging wooden ball, aromatized with vanilla fluid hanging wooden ball and without enrichment was evaluated. It was found that both enrichments reduced aggression, however the most interesting for weaners was the aromatized wooden ball
REAKCJA BEHAWIORALNA WARCHLAKÓW NA DODATKOWE, PODWIESZANE ELEMENTY: DREWNIANĄ PIŁKĘ I AROMATYZOWANĄ DREWNIANĄ PIŁKĘ - MOŻLIWOŚCI OGRANICZENIA AGRESJI PO POŁĄCZENIU MIOTÓW
The behaviour of weaners after mixing housed in pens equipped with hanging wooden ball, aromatized with vanilla fluid hanging wooden ball and without enrichment was evaluated. It was found that both enrichments reduced aggression, however the most interesting for weaners was the aromatized wooden ball.Przeprowadzono obserwacje zachowania warchlaków utrzymywanych po odsadzeniu w kojcach wyposażonych w podwieszaną drewnianą piłkę, aromatyzowaną aromatem waniliowym podwieszaną drewnianą piłkę oraz bez elementów dodatkowych. Stwierdzono, że dodatkowe wzbogacenie środowiska chowu w postaci aromatyzowanej drewnianej piłki spowodowało statystycznie istotne (P<0,05) obniżenie poziomu agresji w porównaniu do grupy bez elementów dodatkowych, jednak obecność nie aromatyzowanej drewnianej piłki również spowodowała skrócenie czasu spędzanego na walkach i obniżenie ich częstotliwości występowania, jakkolwiek nie zostało to potwierdzone statystycznie
Dispersal in a metapopulation of the critically endangered Danube Clouded Yellow butterfly Colias myrmidone : implications for conservation
Colias myrmidone has suffered a dramatic decline in Europe, and now its
occurrence is restricted to just a few countries. We investigated one of
the last viable metapopulations (Knyszyn Forest, NE Poland), where the
butterfly is almost completely dependent on forestry, inhabiting some
clearings and young tree plantations rich in larval food plants
(Chamaecytisus ruthenicus) and nectar resources. Intensive
mark-recapture studies were performed in 2017 on eight occupied patches
separated by 0.5-5km. The overall population size of imagoes in the
second brood was calculated at about 750 individuals. Sex ratio was
shown to be well-balanced and average residency was estimated at 5.6
days. Dispersal occurred mostly between neighbouring patches, and
isolation of patches contributed to the high mortality of emigrants. The
average distance covered during dispersal was significantly higher for
males. However, females left small patches much more readily than males.
These patches were probably used only as stepping stone' sites in
dispersal. Restricted dispersal could be related to barriers created by
forest stands but it is also not excluded that individuals living in an
isolated metapopulation become increasingly sedentary and our results
are an early warning sign. The most distant local population was clearly
isolated, with hardly any immigration from the other populations. To
maintain a network of more stable habitat patches some clearings should
be left deforested and appropriately managed. However this goal is
difficult to achieve under the current forestry rules and therefore
(re)creation of habitats on other available open areas should be
considered
A unique population in a unique area : the Alcon blue butterfly and its specific parasitoid in the Białowieża Forest
Diurnal rhythms of pinealocyte ultrastructure, pineal serotonin content and plasma melatonin level in the domestic pig.
The study was conducted to investigate diurnal changes in pinealocyte ultrastructure, pineal serotonin content and plasma melatonin concentration in the domestic pig. The immature pigs (n=24) were kept under a cycle of 12 h light : 12 h dark, with a photophase between 0800 and 2000. During the photophase the animals were exposed to direct sunlight. After four weeks the gilts were slaughtered at 0900, 1400, 2100 and 0200. The pineals were removed and divided into two parts - one for quantitative ultrastructural study (by a point count method) and one for serotonin assay. Simultaneously, blood samples were taken for melatonin assay. The relative volume of mitochondria in pinealocyte perikarya was significantly higher at 1400 than at 0200 and 0900 as well as at 2100 than at 0200. The relative volume of Golgi apparatus was higher at 0900 and 1400 than at 0200. The relative volume of dense bodies of the MBB-1 type in pinealocyte perikarya was significantly lower at 1400 and 2100 than at 0900. In contrast, the relative volume of MBB-2 was higher at 1400 than at 0900 and 0200. The numerical density of DCV in perikarya was significantly higher at 0200 than at 1400. No significant differences were found in rough endoplasmic reticulum, lysosomes and multivesicular bodies. The pineal serotonin content showed a prominent rhythm with the maximum at 1400. The plasma melatonin concentration was significantly higher at 0200 than at 0900, 1400 and 2100. The obtained results demonstrate that both pinealocyte ultrastructure and pineal biochemistry in the pig undergo significant changes in the course of the diurnal rhythm
Approximation Algorithms for the Joint Replenishment Problem with Deadlines
The Joint Replenishment Problem (JRP) is a fundamental optimization problem
in supply-chain management, concerned with optimizing the flow of goods from a
supplier to retailers. Over time, in response to demands at the retailers, the
supplier ships orders, via a warehouse, to the retailers. The objective is to
schedule these orders to minimize the sum of ordering costs and retailers'
waiting costs.
We study the approximability of JRP-D, the version of JRP with deadlines,
where instead of waiting costs the retailers impose strict deadlines. We study
the integrality gap of the standard linear-program (LP) relaxation, giving a
lower bound of 1.207, a stronger, computer-assisted lower bound of 1.245, as
well as an upper bound and approximation ratio of 1.574. The best previous
upper bound and approximation ratio was 1.667; no lower bound was previously
published. For the special case when all demand periods are of equal length we
give an upper bound of 1.5, a lower bound of 1.2, and show APX-hardness
Streptozotocin-Induced Diabetes Causes Changes in Serotonin-Positive Neurons in the Small Intestine in Pig Model
Serotonin (5-hydroxytryptamine or 5-HT) is an important neurotransmitter of the central
and peripheral nervous systems, predominantly secreted in the gastrointestinal tract, especially in
the gut. 5-HT is a crucial enteric signaling molecule and is well known for playing a key role in
sensory-motor and secretory functions in the gut. Gastroenteropathy is one of the most clinical
problems in diabetic patients with frequent episodes of hyperglycemia. Changes in 5-HT expression
may mediate gastrointestinal tract disturbances seen in diabetes, such as nausea and diarrhea. Based
on the double immunohistochemical staining, this study determined the variability in the population
of 5-HT-positive neurons in the porcine small intestinal enteric neurons in the course of streptozotocininduced
diabetes. The results show changes in the number of 5-HT-positive neurons in the examined
intestinal sections. The greatest changes were observed in the jejunum, particularly within the
myenteric plexus. In the ileum, both de novo 5-HT synthesis in the inner submucosal plexus neurons
and an increase in the number of neurons in the outer submucosal plexus were noted. The changes
observed in the duodenum were also increasing in nature. The results of the current study confirm
the previous observations concerning the involvement of 5-HT in inflammatory processes, and an
increase in the number of 5-HT -positive neurons may also be a result of increased concentration of
the 5-HT in the gastrointestinal tract wall and affects the motor and secretory processes, which are
particularly intense in the small intestines
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