An evolutionarily stable joining policy for group foragers

For foragers that exploit patchily distributed resources that are challenging to locate, detecting discoveries made by others with a view to joining them and sharing the patch may often be an attractive tactic, and such behavior has been observed across many taxa. If, as will commonly be true, the time taken to join another individual on a patch increases with the distance to that patch, then we would expect foragers to be selective in accepting joining opportunities: preferentially joining nearby discoveries. If competition occurs on patches, then the profitability of joining (and of not joining) will be influenced by the strategies adopted by others. Here we present a series of models designed to illuminate the evolutionarily stable joining strategy. We confirm rigorously the previous suggestion that there should be a critical joining distance, with all joining opportunities within that distance being accepted and all others being declined. Further, we predict that this distance should be unaffected by the total availability of food in the environment, but should increase with decreasing density of other foragers, increasing speed of movement towards joining opportunities, increased difficulty in finding undiscovered food patches, and decreasing speed with which discovered patches can be harvested. We are further able to make predictions as to how fully discovered patches should be exploited before being abandoned as unprofitable, with discovered patches being more heavily exploited when patches are hard to find: patches can be searched for remaining food more quickly, forager density is low, and foragers are relatively slow in traveling to discovered patches

Joining of Immunoglobulin Heavy Chain Gene Segments: Implications from a Chromosome with Evidence of Three D-JH Fusions

A chromosomal segment with a unique structure around the immunoglobulin heavy chain joining region (JH) has been molecularly cloned from an Abelson murine leukemia virus-transformed cell line. Attached to JH3 in the cloned DNA, in inverted sequence, is the DNA from JH1 to the JH2 recognition sequence. The inverted segment is attached at its other end to the 5' recognition sequence of a diversity segment (D). To form this structure, three joining events must have occurred on the same chromosome. One of these events could have been a normal D-JH joining but the others must have been irregular events including ones that result in inversions. One of the joining events left fused recognition elements from JH2 and a D whose sequence shows that, during joining, reciprocal joinings of the recognition elements must occur to fuse the heptameric elements back to back. Because joined D and JH undergo deletion of terminal coding sequence during recombination but the joined heptameric recognition sequences do not contain the deleted sequence, joining must be a nonreciprocal event. Also, extra nucleotides are inserted between D and JH as part of the joining process; it is suggested that this added sequence is a product of the activity of terminal deoxynucleotidyltransferase at the D/JH (and probably the VH/D) joints and that it represents a new element of heavy chain gene structure, the N region

Laser Dissimilar Joining of Al7075T6 with Glass-Fiber-Reinforced Polyamide Composite

Dissimilar joining between metal and composite sheets is usually carried out by mechanical or adhesive joining. Laser dissimilar joining between metal and composite sheets could be an alternative to these methods, as it is a cost-effective and versatile joining technique. Previously, textured metallic and composite parts have been held together and heated with a laser beam while pressure is applied to allow the melted polymer to flow into the cavities of the metal part. The main issue of this process relates to reaching the same joint strength repetitively with appropriate process parameters. In this work, both initial texturing and laser joining parameters are studied for Al 7075-T6 and glass-fiber-reinforced PA6 composite. A groove-based geometry was studied in terms of depth-to-width aspect ratio to find an optimal surface using a nanosecond fiber laser for texturing. Laser joining parameters were also studied with different combinations of surface temperature, heating strategy, pressure, and laser feed rate. The results are relatively good for grooves with aspect ratios from 0.94 to 4.15, with the widths of the grooves being the most critical factor. In terms of joining parameters, surface reference temperature was found to be the most influential parameter. Underheating does not allow correct material flow in textured cavities, while overheating also causes high dispersion in the resulting shear strength. When optimal parameters are applied using correct textures, shear strength values over 26 kN are reached, with a contact area of 35 × 45 mm2.This research was funded by the Basque Government grant number KK-2017/00088

Joining and decomposing reaction networks

In systems and synthetic biology, much research has focused on the behavior and design of single pathways, while, more recently, experimental efforts have focused on how cross-talk (coupling two or more pathways) or inhibiting molecular function (isolating one part of the pathway) affects systems-level behavior. However, the theory for tackling these larger systems in general has lagged behind. Here, we analyze how joining networks (e.g., cross-talk) or decomposing networks (e.g., inhibition or knock-outs) affects three properties that reaction networks may possess---identifiability (recoverability of parameter values from data), steady-state invariants (relationships among species concentrations at steady state, used in model selection), and multistationarity (capacity for multiple steady states, which correspond to multiple cell decisions). Specifically, we prove results that clarify, for a network obtained by joining two smaller networks, how properties of the smaller networks can be inferred from or can imply similar properties of the original network. Our proofs use techniques from computational algebraic geometry, including elimination theory and differential algebra.Comment: 44 pages; extensive revision in response to referee comment

Joining Spacetimes on Fractal Hypersurfaces

The theory of fractional calculus is attracting a lot of attention from mathematicians as well as physicists. The fractional generalisation of the well-known ordinary calculus is being used extensively in many fields, particularly in understanding stochastic process and fractal dynamics. In this paper, we apply the techniques of fractional calculus to study some specific modifications of the geometry of submanifolds. Our generalisation is applied to extend the Israel formalism which is used to glue together two spacetimes across a timelike, spacelike or a null hypersurface. In this context, we show that the fractional extrapolation leads to some striking new results. More precisely we demonstrate that, in contrast to the original Israel formalism, where many spacetimes can only be joined together through an intermediate thin hypersurface of matter satisfying some non- standard energy conditions, the fractional generalisation allows these spacetimes to be smoothly sewed together without any such requirements on the stress tensor of the matter fields. We discuss the ramifications of these results for spacetime structure and the possible implications for gravitational physics.Comment: 22 pages, 2 figure

FACTORS THAT MAKE THE STUDENTS INTERESTED INJOINING ENGLISH CONVERSATION EXTRACURRICULAR

Interest has a valuable role in students’ successful learning. Students undoubtedly learn more efficiently things that interest them. The students think that what they are learned about is valuable to them personally. They will participate actively because they know how important the learning is. But every student has different reasons or factors in joining an activity. The purpose of this study was to know students’ interest in joining English conversation extracurricular, factors that make the students interested in joining English conversation extracurricular and the most dominant factor that make the students interested in joining English conversation extracurricular. In this study, the researcher applied descriptive qualitative design to get the data. The population of this research was all members of ECE at SMA N 2 BATU. To get the sample, the researcher chose the students used purposive sampling because the members of ECE consisted of first and second year students of Senior High School. As a result of taking purposive sampling, there were 34 first year students to be taken as the sample of this research. Meanwhile, the instrument used was questionnaire. From the result of the study, it was found that the first year students of ECE had very high interest in joining ECE. There were six factors which made the students interested in joining ECE. The first factor was related to aptitude, only few students join ECE because they had aptitude. The second was that most of the students had capability in English, therefore they join ECE. The third factor was concerned with students’ ideal. The students joined ECE because they wanted to reach their ideal in the future related to English. Therefore, most of the students had very high interest in joining ECE because they had internal factor that was ideals. The fourth factor was concerned with students’ family, few of them were asked by their parents to join ECE. The fifth factor was related to their teacher. The teacher motivated the students by using many kinds of technique in teaching such as games, role play, poem, etc. The last factor was connected to society. Only two students joint ECE because their friends also joined the activity. Besides, the most dominant factor that made the students interested in joining ECE was students’ ideal. The students joined ECE because they wanted to reach their ideal in the future related to English

Radial honeycomb core

Core alleviates many limitations of conventional nacelle construction methods. Radical core, made of metals or nonmetals, is fabricated either by joining nodes and then expanding, or by performing each layer and then joining nodes. Core may also be produced from ribbons or strips with joined nodes or ribbons oriented in longitudinal planes

Stochastic order results and equilibrium joining rules for the Bernoulli Feedback Queue

We consider customer joining behaviour for a system that consists of a FCFS queue with Bernoulli feedback. A consequence of the feedback characteristic is that the sojourn time of a customer already in the system depends on the joining decisions taken by future arrivals to the system. By establishing stochastic order results for coupled versions of the system, we establish the existence of homogeneous Nash equilibrium joining policies for both single and multiple customer types which are distinguished through distinct quality of service preference parameters. Further, it is shown that for a single customer type, the homogeneous policy is unique