To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
A novel reconfigurable circular microstrip G-slotted antenna having a circularly defected ground structure (DGS) capable of switching its resonance frequency for several microwave applications is presented in this paper. Reconfigurability of the proposed G-slot antenna is obtained by incorporating three PIN diodes. One diode is embedded in the patch and two diodes are integrated into the DGS structure at appropriate places in the slot to achieve four different wireless applications such as aeronautical radio navigation (4.3 GHz with gain 3.6 dB), satellite communication (3.78 GHz with gain 3.7 dB), mobile communication (4.55 GHz with gain 4.0 dB), and WiMAX (3.35 GHz with gain 3.3 dB). These four bands are achieved depending on the different biasing conditions of the three PIN switches used. Antenna performance has been analyzed in ANSYS Electronics Desktop 2018.2 software. The equivalent circuit component of the switching element (PIN diode) has been considered and designed during the simulation. The creative structure lies in the way that it exhibits higher gain with compact size than the previously reported similar antenna. A prototype of the proposed patch antenna has been fabricated on a Roger substrate and its testing and measurement have been performed to demonstrate its desirable characteristics and features.
Hypertrophic ‘giant’ handaxes are a rare component of Acheulean assemblages, yet have been central to debates relating to the social, cognitive and cultural ‘meaning’ of these enigmatic tools. The authors examine giant handaxes from the perspective of the British record and suggest that they are chronologically patterned, with the great majority originating from contexts broadly associated with Marine Isotope Stage 9. Giant handaxes tend to have higher symmetry than non-giants, and extravagant forms, such as ficrons, are better represented; they may therefore be linked to incipient aesthetic sensibilities and, potentially, to changing cognition at the transition between the Lower and Middle Palaeolithic.
Autonomous fabric manipulation is a challenging task due to complex dynamics and potential self-occlusion during fabric handling. An intuitive method of fabric-folding manipulation first involves obtaining a smooth and unfolded fabric configuration before the folding process begins. However, the combination of quasi-static actions like pick & place and dynamic action like fling proves inadequate in effectively unfolding long-sleeved T-shirts with sleeves mostly tucked inside the garment. To address this limitation, this paper introduces an enhanced quasi-static action called pick & drag, specifically designed to handle this type of fabric configuration. Additionally, an efficient dual-arm manipulation system is designed in this paper, which combines quasi-static (including pick & place and pick & drag) and dynamic fling actions to flexibly manipulate fabrics into unfolded and smooth configurations. Subsequently, once it is confirmed that the fabric is sufficiently unfolded and all fabric keypoints are detected, the keypoint-based heuristic folding algorithm is employed for the fabric-folding process. To address the scarcity of publicly available keypoint detection datasets for real fabric, we gathered images of various fabric configurations and types in real scenes to create a comprehensive keypoint dataset for fabric folding. This dataset aims to enhance the success rate of keypoint detection. Moreover, we evaluate the effectiveness of our proposed system in real-world settings, where it consistently and reliably unfolds and folds various types of fabrics, including challenging situations such as long-sleeved T-shirts with most parts of sleeves tucked inside the garment. Specifically, our method achieves a coverage rate of 0.822 and a success rate of 0.88 for long-sleeved T-shirts folding. Supplemental materials and dataset are available on our project webpage at https://sites.google.com/view/fabricfolding.
The aim of the Isfahan Anthology Project is to create an inventory of, collect, and digitize all extant anthologies produced in seventeenth-century Isfahan. Thousands of majmuʿa were authored and assembled in Isfahan. Presently, we are working together with our graduate students at the University of Isfahan and the University of Michigan in a collaboration that intends to train a new generation of Safavid historians who will continue this digital project into the future. We have begun the vast project of collecting and generating tables of contents for anthologies housed in the capital's most prominent public libraries—Tehran University Library, Majlis Library, Malik Library, and the National (Milli) Library of Iran—to begin our analysis of their anthology collections. Adapting our work to include reconnaissance, we have taken careful account of the content and organization of these anthologies so that we can create a digital and searchable database of Isfahan's anthologies that allows fellow scholars and graduate students across the world to freely have access to these rich Persianate-world sources.
We generalise and improve some recent bounds for additive energies of modular roots. Our arguments use a variety of techniques, including those from additive combinatorics, algebraic number theory and the geometry of numbers. We give applications of these results to new bounds on correlations between Salié sums and to a new equidistribution estimate for the set of modular roots of primes.
We study some analytic properties of the Asai lifts associated with cuspidal Hilbert modular forms, and prove sharp bounds for the second moment of their central L-values.
Let G be a countable residually finite group (for instance, ${\mathbb F}_2$) and let $\overleftarrow {G}$ be a totally disconnected metric compactification of G equipped with the action of G by left multiplication. For every $r\geq 1$, we construct a Toeplitz G-subshift $(X,\sigma ,G)$, which is an almost one-to-one extension of $\overleftarrow {G}$, having r ergodic measures $\nu _1, \ldots ,\nu _r$ such that for every $1\leq i\leq r$, the measure-theoretic dynamical system $(X,\sigma ,G,\nu _i)$ is isomorphic to $\overleftarrow {G}$ endowed with the Haar measure. The construction we propose is general (for amenable and non-amenable residually finite groups); however, we point out the differences and obstructions that could appear when the acting group is not amenable.
PET imaging is increasingly recognized as an important diagnostic tool to investigate patients with cognitive disturbances of possible neurodegenerative origin. PET with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG), assessing glucose metabolism, provides a measure of neurodegeneration and allows a precise differential diagnosis among the most common neurodegenerative diseases, such as Alzheimer’s disease, frontotemporal dementia or dementia with Lewy bodies. PET tracers specific for the pathological deposits characteristic of different neurodegenerative processes, namely amyloid and tau deposits typical of Alzheimer’s Disease, allow the visualization of these aggregates in vivo. [18F]FDG and amyloid PET imaging have reached a high level of clinical validity and are since 2022 investigations that can be offered to patients in standard clinical care in most of Canada.
This article will briefly review and summarize the current knowledge on these diagnostic tools, their integration into diagnostic algorithms as well as perspectives for future developments.
We show that Kozen and Tiuryn’s substructural logic of partial correctness $\mathsf{S}$ embeds into the equational theory of Kleene algebra with domain, $\mathsf{KAD}$. We provide an implicational formulation of $\mathsf{KAD}$ which sets $\mathsf{S}$ in the context of implicational extensions of Kleene algebra.
This article studies the duplication diacritic of Epigraphic Mayan (ISO 639-3 emy) during the Classic period (a.d. 200–900). Cataloged as grapheme 22A, it consists of two dots optionally and rarely affixed to another grapheme to command the reader, in the majority of cases, to read a syllabogram twice in sequence. This article reviews prior literature on the diacritic, elaborates a typology of four distinct but ultimately related functions, and employs a data set compiled by means of the Maya Hieroglyphic Database to determine via statistical tests whether scriptal, linguistic, media, geographic, and temporal factors were influential in its distribution, and more narrowly, its various functions. The results indicate that two lexemes, käkäw ‘cacao’ and k'ahk’ ‘fire,’ account for several of the scriptal and linguistic traits that show significant relationships with 22A, with the former, käkäw, likely serving as a major prototype in the evolution of 22A. It is also pointed out that 22A is absent from the Postclassic (a.d. 900–1521) codices, suggesting that one of the Classic regional subtraditions with lowest frequency of use of 22A may have been a direct ancestor of the subtraditions responsible for the codices.
The aim of the present study was to report canid attacks on sea turtles in northeastern Brazil. The study was conducted on the Sergipe-Alagoas Basin coastline between March 2010 and October 2019. Injured-stranded sea turtles or carcasses were recorded through systematic beach monitoring. The specimens were submitted for clinical or postmortem assessments, providing evidence for the identification of injuries caused by canids. In the study period, 9841 stranded sea turtles were recorded, with the diagnosis of canid attacks in 55 (0.55%) events. Lepidochelys olivacea was the species with the largest number of events (90.90%), followed by Chelonia mydas (7.27%), and Caretta caretta (1.81%). The attacked sea turtles were clinically healthy, with a good body score and no apparent diseases; most were in the reproductive stage. The injuries were mainly found on the front flippers, with considerable loss of musculature affecting the brachial plexus, with the rupture of large blood vessels, and in some cases, exposure of the humerus or oesophagus. Thus, these events hampered the reproductive cycle, limiting the egg-laying process and preventing the hatching of hundreds of new turtles. Therefore, mitigating measures should be implemented, addressing the consequences of abandoning pets and their unsupervised presence on beaches.
Accurate prediction for mechanisms’ dynamic responses has always been a challenging task for designers. For modeling easiness purposes, mechanisms’ synthesis and optimization have been mostly limited to rigid systems, making consequently the designer unable to vow that the manufactured mechanism satisfies the target responses. To address this limitation, flexible mechanism synthesis is aimed in this work. Two benchmark mechanisms being the core of myriad mechanical devices are of scope, mainly, the flexible slider-crank and the four-bar. In addition to the mechanism dimensions, materials properties have been embedded in the synthesis problem. Two responses are of interest for the slider-crank mechanism, the slider velocity, and the midpoint axial displacement for the flexible connecting rod. Whereas five responses have been compiled for the four-bar mechanism synthesis. A comparative analysis of seven optimization techniques to solve the synthesis problem for both mechanisms has been performed. Subsequently, an executable computer-aided design tool for mechanisms synthesis has been developed under MATLAB®. Numerical outcomes emphasize the limits of a single-response-based synthesis for a flexible mechanism. It has been proven that combining different responses alleviates possible error and fulfill high-accuracy requirement.
Sedentary occupation of the southern Levantine coast spans from the Pre-Pottery Neolithic C to the Early Bronze Age Ib phase (c. 7000–3100 BC). Sites dating to the Early Pottery Neolithic (c. 6400–5500 BC) are scarce, however, potentially reflecting the effects of the 8.2ka climatic event. Here, the authors present the investigations at the submerged site of Habonim North off the Carmel Coast. Typological and radiocarbon dating indicate an Early Pottery Neolithic occupation and evidence for continuity of subsistence and economic strategies with both earlier and later Neolithic cultures. The results indicate the resilience of coastal communities in the face of significant climatic uncertainty and contribute to understanding human responses to environmental change.