DELF: Safeguarding deletion correctness in Online Social Networks

Deletion is a core facet of Online Social Networks (OSNs). For users, deletion is a tool to remove what they have shared and control their data. For OSNs, robust deletion is both an obligation to their users and a risk when developer mistakes inevitably occur. While developers are effective at identifying high-level deletion requirements in products (e.g., users should be able to delete posted photos), they are less effective at mapping high-level requirements into concrete operations (e.g., deleting all relevant items in data stores). Without framework support, developer mistakes lead to violations of users' privacy, such as retaining data that should be deleted, deleting the wrong data, and exploitable vulnerabilities.We propose DELF, a deletion framework for modem OSNs. In DELF, developers specify deletion annotations on data type definitions, which the framework maps into asynchronous, reliable and temporarily reversible operations on backing data stores. DELF validates annotations both statically and dynamically, proactively flagging errors and suggesting fixes.We deployed DELF in three distinct OSNs, showing the feasibility of our approach. DELF detected, surfaced, and helped developers correct thousands of omissions and dozens of mistakes, while also enabling timely recovery in tens of incidents where user data was inadvertently deleted

Biological flora of the British Isles: Sarcocornia perennis (Miller) A.J. Scott

1.This account reviews information on all aspects of the biology of Sarcocornia perennis that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation. 2. Sarcocornia perennis (Miller) A.J. Scott (Salicornia perennis Miller; Salicornia radicans Sm.; Arthrocnemum [Arthrocnemon]perenne (Miller) Moss) of the European and African coasts is now considered also to include Salicornia virginica L., S. ambigua Michx. and S. gaudichaudiana Moq. of the Americas. Sarcocornia perennis is a spreading, jointed-stemmed, halophyte that differs from the closely related Salicornia in being a shrubby perennial and in aspects of inflorescence structure. In Britain, it is found mainly on the coasts of south-east England, on gravelly or sandy foreshores, and well-drained sediments of tidal salt marshes. 3. Sarcocornia perennis occurs relatively low in the tidal frame but only in well-drained situations, as seedling establishment and long-term survival are intolerant of highly reducing surface sediments. It has a role in the early stages of salt-marsh succession, sometimes as the primary colonist on sandy substrates. In southern Europe, its invasion may be facilitated by the raised clonal tussocks of Spartina maritima, a primary colonist; subsequently, S. perennis dominates the tussocks and supports their rapid radial and upward growth by trapping silt. Pollen flow from the high marsh species Sarcocornia fruticosa may allow invasion by hybrids between the two species. 4. Hybridization between the diploid S. perennis and octaploid S. fruticosa in south-west Spain has been confirmed by analysis of random amplified DNA (RAPDs). This has also clarified the relationship between the two subspecies present there (the widely distributed ssp. perennis and the more upright, rigid Iberian endemic ssp. alpini (Lag.) Castroviejo). 5. Sarcocornia perennis maintains low water potentials and a positive carbon balance under highly saline conditions. Salinity treatment had no effect on the efficiency of Photosystem II (Fv/Fm). Total germination was also unaffected by salinity up to 2%, although above this it was progressively inhibited; the reduction in germination at seawater concentrations was mainly osmotically enforced dormancy, which would promote dispersal by tides and currents

The impact of music interventions on motor rehabilitation following stroke in elderly

In Chapter 16, The impact of music interventions on motor rehabilitation following stroke in elderly, Altenmu¨ller and James present music-supported therapy methods to improve poststroke recovery, with a focus on upper limb and gait rehabilitation, as well as on studies targeting cognitive and psychological outcomes. In line with the previous chapters of this section, they conclude that music listening and active musical training can be a strong stimulant for neuroplastic adaptations and behavioral improvements in neurological rehabilitation, mediated by sensory, motor, cognitive, emotional, and neurophysiological processes. Nonetheless, all these authors emphasize methodological limitations to current music-based intervention studies. They provide very important recommendations to consider when designing and assessing the next studies so that music-based interventions in neurorehabilitation can be grounded within a neurobiological understanding of how and why particular brain systems are affected. These considerations should help to improve the relevance of clinical interventions and the scientific demonstration of their efficacy, ultimately increasing patients’ functioning, autonomy, and well-being