Stress impacts differently in distinct brain regions. However, so far few studies have focused on the differential responses triggered by stressful stimuli on the intrinsic functional heterogeneity of the hippocampal axis. In this study, we assessed the functional and structural alterations caused by exposure to a chronic unpredictable stress (CUS) paradigm on the dorsal-ventral axis of the hippocampus. The morphological analysis demonstrated that CUS had opposite outcomes in the structure of the dorsal (DH) and ventral hippocampus (VH): whereas in the DH, stress triggered a volumetric reduction as a result of atrophy of CA3 and CA1 apical dendrites, in the VH there was an increase in hippocampal volume concurrent with the increase of CA3 apical dendrites. In parallel, electrophysiological data revealed that stress led to a decrease in VH LTD. In summary, the present work showed that stress impacts differently on the structure and function of the DH and VH which contributes to better understand the overall spectrum of the central effects of stress.

The notion of κ-tameness of a pseudovariety was introduced by Almeida and Steinberg and is a strong property which implies decidability of pseudovarieties. In this paper we prove that the pseudovariety LSl, of local semilattices, is κ-tame.A finite non-empty set A is called an alphabet and its elements are called letters. A (finite) word on A is a finite sequence w = (a 1 , . . . , a n ) of elements of A, usually written w = a 1 · · · a n . The integer n is called the length of w. The empty sequence, called the empty word, is denoted by 1 and its length is 0. The length of a word w is denoted by |w|. The product of two words w = a 1 a 2 · · · a n and z = b 1 b 2 · · · b m is the word wz = a 1 a 2 · · · a n b 1 b 2 · · · b m . We denote by A * the set of words on A and by A + the set of non-empty words. The set A * (resp. A + ) endowed with the product is a monoid (resp. semigroup) whose identity is the empty word and is called the free monoid (resp. the free semigroup) generated by A.A word w ∈ A + is said to be primitive if it is not a power of another word; that is, if w = u n for some u ∈ A * and n ∈ N implies w = u (and n = 1). Two words w and z are said to be conjugate if there exist words u, v ∈ A * such that w = uv and z = vu. We notice that, if w is a primitive word and z is a conjugate of w, then z is also primitive. Let an order be fixed for the letters of the alphabet A. A Lyndon word is a primitive word which is minimal, with respect to the lexicographic ordering, in its conjugation class.A bi-infinite (resp. right-infinite, left-infinite) word on A is a sequence w = (a n ) n of letters of A indexed by Z (resp. N, −N), also written

In this paper, we establish several decidability results for pseudovariety joins of the form V ∨ W, where V is a subpseudovariety of J or the pseudovariety R. Here, J (resp. R) denotes the pseudovariety of all J-trivial (resp. R-trivial) semigroups. In particular, we show that the pseudovariety V ∨ W is (completely) κ-tame when V is a subpseudovariety of J with decidable κ-word problem and W is (completely) κ-tame. Moreover, if W is a κ-tame pseudovariety which satisfies the pseudoidentity x 1 • • • x r y ω+1 zt ω = x 1 • • • x r yzt ω , then we prove that R ∨ W is also κ-tame.

We present an algorithm to compute the pointlike subsets of a finite semigroup with respect to the pseudovariety R of all finite R-trivial semigroups. The algorithm is inspired by Henckell's algorithm for computing the pointlike subsets with respect to the pseudovariety of all finite aperiodic semigroups. We also give an algorithm to compute J-pointlike sets, where J denotes the pseudovariety of all finite J-trivial semigroups. We finally show that, in contrast with the situation for R, the natural adaptation of Henckell's algorithm to J computes pointlike sets, but not all of them.

This paper is concerned with the structure of semigroups of implicit operations on the pseudovariety LSl of finite locally idempotent and locally commutative semigroups. We depart from a general result of Almeida and Weil to give two descriptions of these semigroups: the first in terms of infinite words, and the second in terms of infinite and bi-infinite words. We then derive some applications.