Socialisation Tactics of the Spectacled Parrotlet (Forpus Conspicillatus)

Behaviour ◽  
1991 ◽  
Vol 119 (1-2) ◽  
pp. 1-29 ◽  
Author(s):  
Kyra Garnetzke-Stollmann ◽  
Dierk Franck

AbstractSpectacled parrotlets live in a complex system of individual relationships throughout their lives. The adults form exclusive pair bonds, addressing all friendly and sexual behaviour patterns to each other. Pair mates cooperate in agonistic situations. As long as they stay close together they hold the same rank-order position. In mate-choice experiments females (not males) significantly preferred a mate which formerly held a high social position. There are also non-exclusive pair bonds, which are far less stable than exclusive ones. Only exclusive pairs have a good chance to occupy a breeding cavity. All group members are synchronized in many of their activities, such as foraging, preening or resting. They are keenly interested in unusual activities of other group members. Social learning, including copying sexual techniques, seems to be essential. After fledging the parents keep their offspring at a distance from a very early stage. Instead of a close parent-offspring relationship the fledglings form sibling groups with their nest mates. Over a period of months siblings remain the main interaction partners for all friendly and playful activities. They also support one another in agonistic situations. In the first months of life even courtship feeding and sexual behaviour are addressed predominantly to siblings. Thus a pair-like relationship is established between siblings, anticipating the permanent pair bond of adults. Single fledglings, deprived of the experience of a sibling group, remained poorly integrated into the group. They developed alternative socialisation tactics, namely (1) joining a host group of unrelated siblings, (2) renewing a friendly partnership with the parents, (3) helping to protect and feed younger siblings or even unrelated fledglings and (4) seeking early partnership with unrelated group members. Out of 10 single fledglings only the one that was accepted by a host sibling group immediately after fledging became well integrated into the whole group and reproduced well. It is argued that sibling groups offer good opportunities for learning partnership and function as a safe basis for exploring the social environment. It is tentatively proposed that single fledglings have a decreased probability of reproductive success.

Author(s):  
Menghan TAO ◽  
Ning XIAO ◽  
Xingfu ZHAO ◽  
Wenbin LIU

New energy vehicles(NEV) as a new thing for sustainable development, in China, on the one hand has faced the rapid expansion of the market; the other hand, for the new NEV users, the current NEVs cannot keep up with the degree of innovation. This paper demonstrates the reasons for the existence of this systematic challenge, and puts forward the method of UX research which is different from the traditional petrol vehicles research in the early stage of development, which studies from the user's essence level, to form the innovative product programs which meet the needs of users and being real attractive.


Author(s):  
Haoyang Meng ◽  
Sheng Dong ◽  
Jibiao Zhou ◽  
Shuichao Zhang ◽  
Zhenjiang Li

Green flash light (FG) and green countdown (GC) are the two most common signal formats applied in green-red transition that provides drivers additional alert before termination of green phase. Due to their importance and function in stop-pass decision-making process, proper use of them has become a critical issue to greatly improve the safety and efficiency of signalized intersections. Gradually e-bike riders have become more important commuters in China, however, the influence of FG or GC on them is not clear yet and need pay more attention to it. This study chooses two almost identical intersections to obtain highly accurate trajectory data of e-bike riders to study their decision-making behaviors under FG or GC. The e-bike riders’ behavior is classified into four categories and is to identify their stop-pass decision points using the acceleration trend. Two binary-logit models were built to predict the stop–pass decision behaviors for the different e-bike rider groups, explaining that the potential time to the stop-line is the dominant independent factor of the different behaviors of GC and FG. Furthermore empirical analysis of decision points indicated that GC provides the earlier stop-pass decision point and longer decision making duration on the one side while results in more complexity of decision making and greater risk of stop-line crossing than FG on the other side.


2005 ◽  
Vol 11 (5) ◽  
pp. 535-546 ◽  
Author(s):  
Anna Kondakov ◽  
Buko Lindner

Bacterial glycolipids are complex amphiphilic molecules which are, on the one hand, of utmost importance for the organization and function of bacterial membranes and which, on the other hand, play a major role in the activation of cells of the innate and adaptive immune system of the host. Already small alterations to their chemical structure may influence the biological activity tremendously. Due to their intrinsic biological heterogeneity [number and type of fatty acids, saccharide structures and substitution with for example, phosphate ( P), 2-aminoethyl-(pyro)phosphate groups ( P-Etn) or 4-amino-4-deoxyarabinose (Ara4N)], separation of the different components are a prerequisite for unequivocal chemical and nuclear magnetic resonance structural analyses. In this contribution, the structural information which can be obtained from heterogenous samples of glycolipids by Fourier transform (FT) ion cyclotron resonance mass spectrometric methods is described. By means of recently analysed complex biological samples, the possibilities of high-resolution electrospray ionization FT-MS are demonstrated. Capillary skimmer dissociation, as well as tandem mass spectrometry (MS/MS) analysis utilizing collision-induced dissociation and infrared multiphoton dissociation, are compared and their advantages in providing structural information of diagnostic importance are discussed.


2017 ◽  
Vol 474 (3) ◽  
pp. 333-355 ◽  
Author(s):  
Chris Ugbode ◽  
Yuhan Hu ◽  
Benjamin Whalley ◽  
Chris Peers ◽  
Marcus Rattray ◽  
...  

Astrocytes play a fundamental role in maintaining the health and function of the central nervous system. Increasing evidence indicates that astrocytes undergo both cellular and molecular changes at an early stage in neurological diseases, including Alzheimer's disease (AD). These changes may reflect a change from a neuroprotective to a neurotoxic phenotype. Given the lack of current disease-modifying therapies for AD, astrocytes have become an interesting and viable target for therapeutic intervention. The astrocyte transport system covers a diverse array of proteins involved in metabolic support, neurotransmission and synaptic architecture. Therefore, specific targeting of individual transporter families has the potential to suppress neurodegeneration, a characteristic hallmark of AD. A small number of the 400 transporter superfamilies are expressed in astrocytes, with evidence highlighting a fraction of these are implicated in AD. Here, we review the current evidence for six astrocytic transporter subfamilies involved in AD, as reported in both animal and human studies. This review confirms that astrocytes are indeed a viable target, highlights the complexities of studying astrocytes and provides future directives to exploit the potential of astrocytes in tackling AD.


2010 ◽  
Vol 08 (02) ◽  
pp. 337-356 ◽  
Author(s):  
SAAD I. SHEIKH ◽  
TANYA Y. BERGER-WOLF ◽  
ASHFAQ A. KHOKHAR ◽  
ISABEL C. CABALLERO ◽  
MARY V. ASHLEY ◽  
...  

While full-sibling group reconstruction from microsatellite data is a well-studied problem, reconstruction of half-sibling groups is much less studied, theoretically challenging, and computationally demanding. In this paper, we present a formulation of the half-sibling reconstruction problem and prove its APX-hardness. We also present exact solutions for this formulation and develop heuristics. Using biological and synthetic datasets we present experimental results and compare them with the leading alternative software COLONY. We show that our results are competitive and allow half-sibling group reconstruction in the presence of polygamy, which is prevalent in nature.


2003 ◽  
Vol 358 (1433) ◽  
pp. 869-873 ◽  
Author(s):  
Gerrit van Meer ◽  
Jasja Wolthoorn ◽  
Sophie Degroote

In higher eukaryotes, glucosylceramide is the simplest member and precursor of a fascinating class of membrane lipids, the glycosphingolipids. These lipids display an astounding variation in their carbohydrate head groups, suggesting that glycosphingolipids serve specialized functions in recognition processes. It is now realized that they are organized in signalling domains on the cell surface. They are of vital importance as, in their absence, embryonal development is inhibited at an early stage. Remarkably, individual cells can live without glycolipids, perhaps because their survival does not depend on glycosphingolipid–mediated signalling mechanisms. Still, these cells suffer from defects in intracellular membrane transport. Various membrane proteins do not reach their intracellular destination, and, indeed, some intracellular organelles do not properly differentiate to their mature stage. The fact that glycosphingolipids are required for cellular differentiation suggests that there are human diseases resulting from defects in glycosphingolipid synthesis. In addition, the same cellular differentiation processes may be affected by defects in the degradation of glycosphingolipids. At the cellular level, the pathology of glycosphingolipid storage diseases is not completely understood. Cell biological studies on the intracellular fate and function of glycosphingolipids may open new ways to understand and defeat not only lipid storage diseases, but perhaps other diseases that have not been connected to glycosphingolipids so far.


Author(s):  
Swee-Suak Ko ◽  
Min-Jeng Li ◽  
Yi-Cheng Ho ◽  
Chun-Ping Yu ◽  
Ting-Ting Yang ◽  
...  

Abstract GAMYB, UDT1, TIP2/bHLH142, TDR, and EAT1/DTD are important transcription factors (TFs) that play a crucial role during rice pollen development. This study demonstrates that bHLH142 acts downstream of UDT1 and GAMYB and works as a “hub” in these two pollen pathways. We show that GAMYB modulates bHLH142 expression through specific binding to the MYB motif of bHLH142 promoter during early stage of pollen development; while TDR acts as a transcriptional repressor of the GAMYB modulation of bHLH142 by binding to the E-box close to the MYB motif on the promoter. The altered expression of TFs highlights the importance that a tight, precise, and coordinated regulation among these TFs is essential for normal pollen development. Most notably, this study illustrates the regulatory pathways of GAMYB and UDT1 that rely on bHLH142 in a direct and an indirect manner, respectively, and function in different tissues with distinct biological functions during pollen development. This study advances our understanding of the molecular mechanisms of rice pollen development.


2021 ◽  
Author(s):  
Fang Zhou ◽  
Chang Su ◽  
Shuqi Xu ◽  
Linyuan Lü

Abstract In real-world networks, there usually exist a small set of nodes that play an important role in the structure and function of networks. Those vital nodes can influence most other nodes in the network via a spreading process. While most of the existing works focused on vital nodes that can maximize the spreading size in the final stage, which we call final influencers, recent work proposed the idea of fast influencers, which emphasizes nodes’ spreading capacity at the early stage. Despite the recent surge of efforts in identifying these two types of influencers in networks, there remained limited research on untangling the differences between fast influencers and final influencers. In this paper, we first distinguish the two types of influencers: fast-only influencers and final-only influencers. The former is defined as individuals who can achieve a high spreading effect at the early stage but lose their superiority in the final stage, and the latter are those individuals that fail to exhibit a prominent spreading performance at the early stage but influence a large fraction of nodes at the final stage. Further experiments based on eight empirical datasets, we reveal the key differences between the two types of influencers concerning their spreading capacity and the local structures. We also analyze how network degree assortativity influences the fraction of the proposed two types of influencers. The results demonstrate that with the increase of degree assortativity, the fraction of the fast-only influencers decreases, which indicates that more fast influencers tend to keep their superiority at the final stage. Our study provides insights into the differences and evolution of different types of influencers and has important implications for various empirical applications, such as advertisement marketing, and epidemic suppressing.


1998 ◽  
Vol 111 (16) ◽  
pp. 2315-2327 ◽  
Author(s):  
B.J. Cha ◽  
B. Error ◽  
D.L. Gard

We used affinity-purified polyclonal antibodies to characterize the distribution and function of XMAP230, a heat-stable microtubule-associated protein isolated from Xenopus eggs, during oogenesis. Immunoblots revealed that XMAP230 was present throughout oogenesis and early development, but was most abundant in late stage oocytes, eggs, and early embryos. Immunofluorescence microscopy revealed that XMAP230 was associated with microtubules in oogonia, post-mitotic stage 0 oocytes, early stage I oocytes, and during stage IV-VI of oogenesis. However, staining of microtubules by anti-XMAP230 was not detectable during late stage I through stage III. In stage VI oocytes, anti-XMAP230 stained a large subset of microtubules that were also stained with monoclonal antibodies specific for acetylated (α)-tubulin. During oocyte maturation, XMAP230 was associated with the transient microtubule array that serves as the precursor of the first meiotic spindle, as well as both first and second meiotic spindles. The extensive array of cytoplasmic microtubules present throughout maturation was not detectably stained by anti-XMAP230. Microinjection of anti-XMAP230 locally disrupted the organization and acetylation of microtubules in stage VI oocytes, and reduced the re-acetylation of microtubules during recovery from cold-induced microtubule disassembly. Subsequent maturation of oocytes injected with anti-XMAP230 resulted in defects in the assembly of the transient microtubules array and first meiotic spindle. These observations suggest that XMAP230 is required for the stabilization and organization of cytoplasmic and spindle microtubules in Xenopus oocytes and eggs.


2009 ◽  
pp. 163-172
Author(s):  
Angelo Abignente

- The positive law tradition has hitherto had nothing to say about the legal profession's role and function, focusing more interest on questions of justice, of the legitimisation of power and of the genesis and organisation of normative material. This trend is now subject to a reversal promoted by new, neo-constitutionalist, narrativist, analytical and hermeneutic experiences, which no longer focuses attention on the moment when law is produced, but on the one when it is applied, reappraising and revitalising the function of the judge, of the attorneys and of other legal professionals. The attorney becomes an active protagonist, an intermediary not only between conflicting interests in a controversy, but also between opposing public interests, while the reappraisal of his role stimulates thinking about the ethical dimension of how the legal profession is practised. Referring to the theories of Habermas and of Alexy, the author treats the reasonable status of argumentation as the supreme ethical instance necessary for a decision that interferes in the sphere of another person's action. At the same time, however, the control of the reasonable status of the respective arguments on both sides is the ethical instance required of the attorneys taking part in the legal proceedings. It takes the form of compliance with the rules characteristic of the practical discourse, primarily the rule of free discursive participation that enables the onus of the argumentation to be explained. Ernesto de


Sign in / Sign up

Export Citation Format

Share Document