Miracle-dz/UniFAR-FTUs huggingface dataset:
Dispersal and the Stability of Predator-Prey Interactions

A predator-prey interaction between spatially dispersed populations can be considered as many local interactions connected by dispersal. Even when the local subsystems (cells) quickly become extinct in isolation, an ensemble of interconnected cells can, under certain conditions, persist much longer. These conditions include: (1) sufficiently low exchange rates among cells; or (2) a sufficiently high level of environmental stochasticity (noise), either of which can prevent local populations from becoming synchronized; or (3) a large number of cells within the system. Computer simulations based on a broadly applicable predator-prey model demonstrate the efficacy of the conditions 1-3; neither spatial structure (texture) nor density-dependent dispersal are additionally required to obtain long-term persistence. The critical problem of avoiding synchrony in a spatially contiguous, locally unstable system can apparently be solved by size alone. If the system is large enough, it should tend to fragment into two or more hypercell subsystems with the low exchange rates that permit these subsystems to remain out of phase with each other. Environmental noise that is spatially correlated on scales somewhat smaller than the size of the system may also generate or help maintain the hypercells. These features create a mosaic of fluctuating subpopulations that can yield remarkably constant population densities for the system as a whole.
The Mammalian Oviduct: Aspects on Auto‐and Paracrine Mechanisms

Contents This review will present a characterization of basic molecular processes in the mammalian oviduct. Oviducts of the cow (Bos taurus) were examined during the various cycle stages using a combination of cell biology- and molecular-biology techniques [reverse transcriptase polymerase chain reaction (RT-PCR), RNase protection assay (RPA), immunohistology, radio-immunoassay (RIA), receptor-assay, cell culture]. In detail the oviductal expression of the following components was analysed: fibroblast (FGF) and vascular-endothelial (VEGF) growth factor systems; extracellular matrix (ECM) enzymes such as plasminogenactivator (PA) and matrixmetalloproteases (MMP), adrenergic receptors (α2 and β2 AdR) and an anti-oxidative protein (glutathionperoxidase = GPx). A specific cycle-dependant and local regulation of the expression could be demonstrated, not only for growth factors such as FGF1 and VEGF but also for ECM components. Remarkable progesterone-dependent increases of the β2 adrenoceptor concentrations were found in the oviductal epithelium. New observations showed the presence of antioxidative enzymes (GPx) in the bovine oviduct possibly interacting with the gametes. Obviously, a network of local factors seems to influence the function of the oviduct, controlled by peripheral hormones. Cycle–dependent interactions between the growth factor, ECM and adrenergic systems will create the optimal environment for fertilization and early embryo development in the mammalian oviduct.
The effect of 8 days of microgravity on regeneration of intact plants from protoplasts

The growth and development of protoplasts of rapeseed (Brassica napus L. cv Line) and carrot (Daucus carota L. cv. Navona) were studied onboard the Space Shuttle‘Discovery’during an 8-day International Microgravity Laboratory [IML-l) mission in January 1992. The Flight experiments were carried out in‘Biorack'. a fully controlled cell biological experimental facility. under microgravity conditions and in a l-g centrifuge. Parallel experiments were performed in a‘Biorack’module on the ground. After retrieval, some samples were subcultured on appropriate media and analysed for callus growth and regeneration to intact plants. The remainder were used for biochemical analysis. Samples fixed on board the Space Shuttle were kept in l% glutaraldehyde fixative at 4°C for 3–7 days for microscopy analysis after retrieval. Protoplasts exposed to microgravity conditions showed a delay in cell wall synthesis. Cells were swollen in appearance and formed cell aggregates with only few cells. Callus were obtained from protoplasts cultured under microgravity (Fogl). on the l-g centrifuge on board the shuttle (Flg), under normal l-g conditions on the ground (G1g) and on a centrifuge on the ground giving 1.4 g (Gl.4g). Regeneration of intact rapeseed plants was obtained from Flg. Glg and G1.4g. However, no plants were regenerated from protoplasts exposed to microgravity (Fog). Biochemical analysis indicated that the microgravity samples (Fog displayed a reduced packed cell volume, an increased concentration of soluble proteins per cell, and a reduced specific activity of peroxidase in the cytoplasm. Morphometric analysis of fixed samples demonstrated that 3-day old protoplasts under microgravity conditions were significantly larger than protoplasts kept on the l-g centrifuge in space. UItrastructural analysis by transmission electron microscopy showed that protoplasts exposed to microgravity conditions for 3 days had larger vacuoles and a slightly reduced starch content compared to Flg cells. Cell aggregates formed under microgravity conditions (Fog) had an average of 2–I cells per aggregate while aggregates formed under Flg had 8–12 cells.
Determinants of Firms’ Acquisition Ability and its Impact on Cost Efficiency, Operational Hedging and Returns of Acquirer Firms in Pakistan

Abstract: The capital markets witness phenomenal shifts of corporate control. With the shift of world economy into a global one, there has been a rapid increase in the volume of acquisitions. The previous studies shed light on the motives behinds acquisition and its impact on both bidding and target firm. Less effort has been placed to check the ability of a firm dealing in market of corporate control. This study is bridging in the gap in literature by exploring the factors affecting the acquisition ability of the firm. The study has analysed the role of financial strength, corporate governance related variables and regulatory influence on acquisition ability of acquiring firm. Later on, impact of such acquisition ability has been tested on various firm characteristics like cost efficiency, returns and operational hedging of acquirer firms. Data has been analysed with respect to Pakistan stock Exchange for a period of 2004 to 2012. Empirical analysis indicates that firm specific variables are important determinants in firm’s decision to acquire. Chief Executive Officer duality and institutional shareholders presence on the board contributes to this important phenomenon in the life of the acquiring firms. Bidding firm’s financial strength is also another important considerations. The empirical results indicate the better acquisition ability for firms characterized by minimum capacity utilization, lower level of intangible assets, lower debt levels and lower advertising expenses. Acquisition announcement is an important event in the capital markets. The event study technique indicates the significant abnormal returns after 3 days of acquisition announcement. Cost efficiency has been analysed for bidding firms three years prior to the acquisition and three years post acquisition. Overall results suggest an improvement in the efficiency of financial firms after acquisition. Non-financial sector is indicating opposite results where most of the firms are showing declining trend in efficiency. The percentage change in operational volatility is accounted for as operational hedging. The empirical results show a large level decrease in the operational income volatility after the takeover deal. It shows that combined firm after acquisition bring the benefit of diversification thus reducing volatility and increasing operational hedging which may ultimately reduce financial hedging. So acquiring firms should analyse their strength before going for acquisition deal as acquisition impact their short term and long term performance. ​
Intracellular cAMP‐modulated gate in Hyperpolarization activated cation channels

Abstract Hyperpolarization‐activated nonselective cation channels (HCNs) play a pivotal role in producing rhythmic electrical activity in the heart and the nerve cells. In our previous experiments, voltage‐dependent Cd2+ access to one of the substituted cysteines in S6, T464C, supports the existence of an intracellular voltage‐dependent activation gate. Direct binding of intracellular cAMP to HCN channels also modulates gating. Here we attempted to locate the cAMP‐modulated structure that can modify the gating of HCN channels. SpHCN channels, a sea urchin homologue of the HCN family, became inactivated rapidly and intracellular cAMP removed this inactivation, resulting in about eight‐fold increase of steady‐state current level. T464C was probed with Cd2+ applied to the intracellular side of the channel. We found that access of Cd2+ to T464C was strongly gated by cAMP as well as voltage. Release of bound Cd2+ by DMPS was also gated in a cAMP‐dependent manner. Our results suggest the existence of an intracellular cAMP‐modulated gate in the lower S6 region of spHCN channels.
Preparation of fermentation media from agricultural wastes and their bioconversion into xylitol

Abstract Three agricultural wastes with high xylan content (barley bran, corn cobs and corn leaves) were hydrolysed with dilute sulphuric acid solutions under a variety of operational conditions in order to obtain xylose solutions suitable as fermentation media. The operational conditions for hydrolysis were selected on the basis of both the kinetic models developed for xylose generation and the concentrations of reaction byproducts affecting fermentation. Hydrolysates were supplemented with nutrients and fermented with Debaryomyces hansenii without any previous detoxification stage. Experimenal data concernmg batch fermentations are compared to the results obtained in the fermentation of hydrolysates from Eucalyptus wood, a typical raw material for prehydrolysis processes.
Multiplication in vitro d'une espèce menacée, endémique de l'île de La Martinique: Polygala antillensis Chodat, Polygalaceae

Abstract Polygala antillensis (Polygalaceae) is an endemic plant from La Martinique island that is classified critically endangered. The in vitro introduction of this genotype was performed with seeds and fresh nodes (explants). After desinfection, seeds explants generated in vitro plantlets and were multiplied in vitro either by classical micropropagation (on MS or WPM medium without growth regulator) or by adventive bud regeneration (on MS medium with TDZ at 0,3 mg/l). These results allow to consider the reintroduction of this species in protected areas.
O gênero Bulbophyllum Thouars (Orchidaceae) na Chapada Diamantina, Bahia, Brasil

The Chapada Diamantina is located in the northern region of the Espinhaco Range, and its main vegetation type is the "campo rupestre", but other vegetational types also occur such as gallery forests, cerrado and caatinga, and the whole region presents high endemism. Bulbophyllum Thouars is the largest genus of Orchidaceae, with nearly 1.200 species. Fifty-eight Bulbophyllum species are recognized from Brazil, and only five of them were until recently reported for the Bahia state. In this study we present a survey of the Bulbophyllum species occurring in the Chapada Diamantina, based on herbarium and field collections. We found 12 Bulbophyllum species and one natural hybrid in the Chapada Diamantina, eight of which are new occurrences for the state. Bulbophyllum epiphytum Barb. Rodr. , B. laciniatum (Barb. Rodr.) Cogn. , and B. napellii Lindl. are epiphytic; B. involutum Borba, Semir & F. Barros, B. mentosum Barb. Rodr. , B. roraimense Rolfe, B. weddellii (Lindl.) Rchb. f. , and B. ×cipoense Borba & Semir occur exclusively as rupicolous; and B. chloropterum Rchb. f. , B. cribbianum Toscano, B. ipanemense Hoehne, B. manarae Foldats and B. plumosum (Barb. Rodr.) Cogn. present facultative habit. Bulbophyllum ipanemense is the most abundant species of the genus in the Chapada Diamantina, and the populations of this species in Bahia present several morphological differences in relation to the populations of Southeastern region. B. manarae and B. roraimense, formerly considered as endemic to Venezuela, are mentioned for the first time to Brazil, strengthening the hypothesis of a close relationship between the flora of that country and the Chapada Diamantina.
Physiological ecology of nest construction and protein flow in pre-emergence colonies of Polistes chinensis (Hymenoptera Vespidae): effects of rainfall and microclimates

The amount of oral secretion, which mostly consists of proteinaceous materials, used for the construction and maintenance of nests by foundresses of Polistes chinensis was analysed in 95 field nests (1994–1996). The amounts always exceeded 50% of mean percent secretion to total the dry nest weights, and it was greater in nests built at sites exposed to direct rainfall than in those at sheltered sites. Further, exposed nests built in 1995 (a rainy year) were much smaller than those of 1994 and 1996, and the amount of secretion in that year was much greater than in the other years. The nitrogen content of adult workers, immatures, those left inside cells and the oral secretion in nests of 1996 showed that 10–20% of total protein resources brought in during the founding phase may be devoted to producing the secretion. The results suggest that the foundresses may regulate the amounts of oral secretion used for such purposes in response to environmental conditions.
Occurrence of terpenoid aldehydes and lysigenous cavities in the 'glandless' seeds of Australian Gossypium species

The presence of lysigenous cavities filled with terpenoid aldehydes (generically termed 'gossypol') in most tissues of cultivated cottons and their relatives imparts natural resistance to a variety of insect, fungal, and bacterial pests. Deposition of terpenoid aldehydes in cultivated cotton seed, however, renders cottonseed oils and protein meals toxic to non-ruminant animals, including humans. Seeds of the so-called 'glandless-seeded' Australian Gossypium L. species (Gossypium subgenus Sturtia (R.Br.) Tod. ) reportedly lack terpenoid aldehydes, and thus may represent an important genetic resource in the development of cottonseed oils and protein meals free of these toxins. Information supporting this assertion, however, is fragmentary and contradictory. To resolve this, seeds of all known Australian Gossypium species were surveyed chemically and anatomically. Immature lysigenous cavities were present in seeds of all 18 species. Lysigenous cavities of sect. Sturtia and sect. Hibiscoidea Tod. seeds were unpigmented and invisible to the naked eye, while pigmented, macroscopically visible lysigenous cavities occurred in all the sect. Grandicalyx (Fryxell) Fryxell seeds. HPLC (high performance liquid chromatography) analysis revealed that sect. Sturtia and sect. Hibiscoidea seeds did not contain detectable levels of terpenoid aldehydes, but that sect. Grandicalyx seeds contained gossypol.
Grazing in Lake Erken

The seasonal cycles of plants, animals, detritus, and nutrients have been studied in Lake Erken in Sweden by Nauwerck and Pechlaner. The animal populations are heavier by weight than the algal populations by a factor of about five. Both investigators have suggested that the animals do not control the algal populations; Nauwerck suggests that the copepods, at least, subsist on bacteria and detritus. This paper attempts to show that the algae are controlled by the grazing animals and that the proportions by weight are those expected. Nauwerck (1963) published a full acdinoflagellates; weekly volumes were avercormt of the relation between zooplankton aged for all depths. The production rates and phytoplankton in Lake Erken in Sweden. Observation of irradiance, and volare assumed to be common to all algal groups. The samples of volume were taken umes of six groups of algae and four groups weekly and the radiocarbon observations of zooplankton were made each week at about every 2 weeks, and the estimates of depths of 1, 3, 7, 11, 15, and 19 m for a production (as described below) were made year. It is one of the fullest accounts of an aquatic production cycle in existence. Here every 2 weeks; the estimates of average alI reanalyze part of his data. gal reproductive rate were interpolated to obtain an average over the 2 weeks.
Modeling Anthesis to Silking in Maize Using a Plant Biomass Framework

The capacity to predict time to silking relative to anthesis in maize (Zea mays L.) has important implications for breeding and seed production. We developed a theoretical quantitative framework for simulating the anthesis to silking interval (ASI) based on plant growth and biomass partitioning to the ear. We tested this framework to simulate the progress of silking relative to anthesis in nine inbreds and four hybrids whose plant growth rate (PGR) during fl owering was altered by stand density, thinning, or defoliating treatments. Time to 50% anthesis varied with genotype but was not affected by canopy modifi cations (P < 0.01). The ASI, however, varied with genotype and canopy modifi cations (P < 0.01). The proportion of plants reaching silking ranged from 12 to 100% across treatments. There were signifi cant (P < 0.001) genotype × treatment interactions for PGR around anthesis and plantto-plant variability in growth rate. Genotypes differed in biomass partitioning to the ear, the pattern of ear biomass (EB) accumulation, and the EB required to achieve silking. Despite these effects, the plant biomass framework accurately simulated silking dynamics relative to anthesis for the 36 treatment combinations (R 2 = 0.86, RMSE = 16.7%). These results show that coupling the expansion growth process of silking with plant growth around fl owering is a useful and robust approach for modeling ASI at the population level.
Baseline Susceptibility of Creontiades signatus1 to Cotton Insecticides, with Emphasis on Malathion

Abstract. We report the susceptibility of a green plant bug, Creontiades signatus Distant, a pest of cotton, Gossypium hirsutum L. , and other crops in South Texas, to malathion and other cotton insecticides using the adult vial test, and an oral “floral foam” assay for systemic insecticides, when active eradication of boll weevil, Anthonomus grandis grandis Boheman, has been in effect for six seasons in the Rio Grande Valley of Texas. Field-collected green plant bugs exhibited malathion tolerance ratios of 1.68 to 4.83 when compared to unexposed plant bugs reared in the laboratory for six generations. The associated 95% C.l. 's for LC50 values did not overlap following six consecutive paired (field versus laboratory) assays from November 2006 to October 2009. The greater tolerance ratios and LC50 values may be the result of an average of 18 to 20 applications of ultra-low volume (ULV) malathion applied in the process of boll weevil eradication in cotton fields. Field-collected green plant bugs also had larger LC50 values when exposed to acephate using an adult vial test compared to the laboratory strain, but the 95% C.l. s did not overlap. All other organophosphate, pyrethroid, carbamate, neonicotinoid, and flonicomid insecticides were very toxic against field- and laboratory-reared green plant bugs. The floral foam method of diluting non-acetone soluble insecticide active ingredients into honey-water worked well as an assay technique with the exception that mortality should be observed at 72 instead of 48 hours.
Dependence of removal of sperm‐specific proteins from Xenopus sperm nuclei on the phosphorylation state of nucleoplasmin

In Xenopus laevis, nucleoplasmin from fully grown oocytes is not highly phosphorylated, but is more extensively phosphorylated during oocyte maturation to retain this state until mid‐blastula transition. Incubation of demembranated sperm with nucleoplasmin from oocytes or mature eggs revealed that egg nucleoplasmin is twice as potent as oocyte nucleoplasmin in removing sperm‐specific basic proteins from chromatin (protamine‐removing activity: PRA). Dephosphorylation of egg nucleoplasmin by alkaline phosphatase induced a remarkable decline of PRA in nucleoplasmin. Treatment of oocyte nucleoplasmin with cdc2 protein kinase induced an increase of the extent of phosphorylation, but to a level lower than that exhibited by egg nucleoplasmin, suggesting the involvement of other unspecified kinase(s) in phosphorylating nucleoplasmin during oocyte maturation. Incubation of sperm with cdc2 kinase induced selective phosphorylation of sperm‐specific basic proteins, accompanied by their enhanced removal from sperm chromatin upon exposure to high‐salt solutions. These results suggest that removal of sperm‐specific basic proteins from sperm chromatin in fertilized eggs is facilitated by phosphorylation of both nucleoplasmin and sperm‐specific basic proteins.
In situ H2 production and utilization by natural populations of N2-fixing blue-green algae

Contemporaneous in situ acetylene-reduction, 15N2-fixation, and 3H2-exchange assays reveal parallel patterns of N2 fixation and H2 utilization in natural populations of the blue-green algae Anabaena and Aphanizomenon. As spring and summer blooms progress, increasing ratios of acetylene reduction versus 15N2 fixation closely follow elevated rates of cellular H2 utilization. Both acetylene-reduction and H2-utilization rates were largely attributable to blue-green algae as opposed to associated bacteria and other phytoplankton. It is concluded that elevated H2 utilization reflects increased H2 production via nitrogenase. This can be substantiated by monitoring rising acetylene-reduction versus 15N2-fixation ratios during bloom development. Simultaneous deployment of the above techniques provides evidence for (a) in situ H2 production and (b) seasonal trends in rates of H2 production among natural blue-green algal populations.
The Role of the Cytoskeleton and Dictyosome Activity in the Pulsatory Growth of Nicotiana tabacum and Petunia hybrida Pollen Tubes

: Pollen tubes of Nicotiana tabacum and Petunia hybrida show pulsatory growth. Phases of slow growth lasting minutes are interrupted by pulse-like elongations lasting 10–20 seconds involving an increase of growth rate by up to 24-fold. Inhibition of dictyosome activity with brefeldin A or monensin did not result in an inhibition of pulsatory growth but eventually stopped pollen tube elongation. In contrast to this the inhibition of the cytoskeletal elements with cytochalasin D and colchicine caused the pollen tubes to abandon the pulse-like elongations. It was concluded that the activity of the dictyosomes does not have a controlling function in the mechanism of pulsatory growth, even though it is necessary for pollen tube elongation, since cell wall material is provided by secretory vesicles deriving from the Golgi apparatus. In contrast the cytoskeletal elements, actin and microtubules, seem to play an important regulatory role in the pulse-like elongations. In addition, it was observed that during the experiments several pollen tubes burst upon the completion of a pulse-like expansion, indicating on the one hand that the internal turgor is the driving force of the pulse-like expansions. On the other hand, the bursting shows that the pollen tube cell wall is rather weak at the end of a pulse, indicating that at this point of time it is either thinner or less stable than during the slow growth phase or at the beginning of a pulse.
Structure of thermoplasmaquinone from Thermoplasma acidophilum

The structure of the methyl-substituted menaquinone (designated thermoplasmaquinone) from the extremely thermophilic and acidophilic archaebacterium Thermoplasma acidophilum was investigated by mass spectrometry and proton nuclear magnetic resonance spectrometry. The results of the present study show that the novel quinone from T. acidophilum corresponds to 2,[5 or 8]-dimethyl-3-heptaprenyl-1,4-naphthoquinone.