Fixational Instability and Natural Image Statistics: Implications for Early Visual Representations

Under natural viewing conditions small movements of the eye, head, and body prevent the maintenance of a steady direction of gaze. It is known that stimuli tend to fade when they a restabilized on the retina for several seconds. However; it is unclear whether the physiological motion of the retinal image serves a visual purpose during the brief periods of natural visual fixation. This study examines the impact of fixational instability on the statistics of the visua1 input to the retina and on the structure of neural activity in the early visual system. We show that fixational instability introduces a component in the retinal input signals that in the presence of natural images, lacks spatial correlations. This component strongly influences neural activity in a model of the LGN. It decorrelates cell responses even if the contrast sensitivity functions of simulated cells arc not perfectly tuned to counterbalance the power-law spectrum of natural images. A decorrelation of neural activity at the early stages of the visual system has been proposed to be beneficial for discarding statistical redundancies in the input signals. The results of this study suggest that fixational instability might contribute to establishing efficient representations of natural stimuli.

The VITEWRITE Model of Handwriting Production

This article describes the VITEWRITE model for generating handwriting movements. The model consists of a sequential controller, or motor program, that interacts with a trajectory generator to move a hand with redundant degrees of freedom. The neural trajectory generator is the Vector Integration to Endpoint (VITE) model for synchronous variable-speed control of multijoint movements. VITE properties enable a simple control strategy to generate complex handwritten script if the hand model contains redundant degrees of freedom. The controller launches transient directional commands to independent hand synergies at times when the hand begins to move, or when a velocity peak in the outflow command to a given synergy occurs. The VITE model translates these temporally disjoint synergy commands into smooth curvilinear trajectories among temporally overlapping synergetic movements. Each synergy exhibits a unimodal velocity profile during any stroke, generates letters that are invariant under speed and size rescaling, and enables effortless connection of letter shapes into words. Speed and size rescaling are achieved by scalar GO and GRO signals that express computationally simple volitional commands. Psychophysical data such as the isochrony principle, asymmetric velocity profiles, and the two-thirds power law relating movement curvature and velocity arise as emergent properties of model interactions.

Adaptive Neural Networks for Control of Movement Trajectories Invariant under Speed and Force Rescaling

This article describes two neural network modules that form part of an emerging theory of how adaptive control of goal-directed sensory-motor skills is achieved by humans and other animals. The Vector-Integration-To-Endpoint (VITE) model suggests how synchronous multi-joint trajectories are generated and performed at variable speeds. The Factorization-of-LEngth-and-TEnsion (FLETE) model suggests how outflow movement commands from a VITE model may be performed at variable force levels without a loss of positional accuracy. The invariance of positional control under speed and force rescaling sheds new light upon a familiar strategy of motor skill development: Skill learning begins with performance at low speed and low limb compliance and proceeds to higher speeds and compliances. The VITE model helps to explain many neural and behavioral data about trajectory formation, including data about neural coding within the posterior parietal cortex, motor cortex, and globus pallidus, and behavioral properties such as Woodworth's Law, Fitts Law, peak acceleration as a function of movement amplitude and duration, isotonic arm movement properties before and after arm-deafferentation, central error correction properties of isometric contractions, motor priming without overt action, velocity amplification during target switching, velocity profile invariance across different movement distances, changes in velocity profile asymmetry across different movement durations, staggered onset times for controlling linear trajectories with synchronous offset times, changes in the ratio of maximum to average velocity during discrete versus serial movements, and shared properties of arm and speech articulator movements. The FLETE model provides new insights into how spina-muscular circuits process variable forces without a loss of positional control. These results explicate the size principle of motor neuron recruitment, descending co-contractive compliance signals, Renshaw cells, Ia interneurons, fast automatic reactive control by ascending feedback from muscle spindles, slow adaptive predictive control via cerebellar learning using muscle spindle error signals to train adaptive movement gains, fractured somatotopy in the opponent organization of cerebellar learning, adaptive compensation for variable moment-arms, and force feedback from Golgi tendon organs. More generally, the models provide a computational rationale for the use of nonspecific control signals in volitional control, or "acts of will", and of efference copies and opponent processing in both reactive and adaptive motor control tasks.

A Neural Network of Adaptively Timed Reinforcement Learning and Hippocampal Dynamics

A neural model is described of how adaptively timed reinforcement learning occurs. The adaptive timing circuit is suggested to exist in the hippocampus, and to involve convergence of dentate granule cells on CA3 pyramidal cells, and NMDA receptors. This circuit forms part of a model neural system for the coordinated control of recognition learning, reinforcement learning, and motor learning, whose properties clarify how an animal can learn to acquire a delayed reward. Behavioral and neural data are summarized in support of each processing stage of the system. The relevant anatomical sites are in thalamus, neocortex, hippocampus, hypothalamus, amygdala, and cerebellum. Cerebellar influences on motor learning are distinguished from hippocampal influences on adaptive timing of reinforcement learning. The model simulates how damage to the hippocampal formation disrupts adaptive timing, eliminates attentional blocking, and causes symptoms of medial temporal amnesia. It suggests how normal acquisition of subcortical emotional conditioning can occur after cortical ablation, even though extinction of emotional conditioning is retarded by cortical ablation. The model simulates how increasing the duration of an unconditioned stimulus increases the amplitude of emotional conditioning, but does not change adaptive timing; and how an increase in the intensity of a conditioned stimulus "speeds up the clock", but an increase in the intensity of an unconditioned stimulus does not. Computer simulations of the model fit parametric conditioning data, including a Weber law property and an inverted U property. Both primary and secondary adaptively timed conditioning are simulated, as are data concerning conditioning using multiple interstimulus intervals (ISIs), gradually or abruptly changing ISis, partial reinforcement, and multiple stimuli that lead to time-averaging of responses. Neurobiologically testable predictions are made to facilitate further tests of the model.

A Neural Network Model for Cursive Script Production

This article describes a neural network model, called the VITEWRITE model, for generating handwriting movements. The model consists of a sequential controller, or motor program, that interacts with a trajectory generator to move a. hand with redundant degrees of freedom. The neural trajectory generator is the Vector Integration to Endpoint (VITE) model for synchronous variable-speed control of multijoint movements. VITE properties enable a simple control strategy to generate complex handwritten script if the hand model contains redundant degrees of freedom. The proposed controller launches transient directional commands to independent hand synergies at times when the hand begins to move, or when a velocity peak in a given synergy is achieved. The VITE model translates these temporally disjoint synergy commands into smooth curvilinear trajectories among temporally overlapping synergetic movements. The separate "score" of onset times used in most prior models is hereby replaced by a self-scaling activity-released "motor program" that uses few memory resources, enables each synergy to exhibit a unimodal velocity profile during any stroke, generates letters that are invariant under speed and size rescaling, and enables effortless. connection of letter shapes into words. Speed and size rescaling are achieved by scalar GO and GRO signals that express computationally simple volitional commands. Psychophysical data concerning band movements, such as the isochrony principle, asymmetric velocity profiles, and the two-thirds power law relating movement curvature and velocity arise as emergent properties of model interactions.

Legislative policy, law and competitiveness: a mysterious and difficult relationship in the EU

The Lisbon Agenda places Europe in a uniquely difficult position globally, most particularly as an example of a social and regulatory experiment which many consider to be doomed to failure. The drive towards economic competitiveness has led to a focus on regulation and its effect on entrepreneurship, productivity and business growth but assessing this relationship is complex for a number of reasons. First, not all regulatory effects can be predicted precisely in relation to behavioural outcomes. Path-dependency scholars have also demonstrated that the regulation will have varying effects depending on context. Second, theoretically it is clear that many non-regulatory factors may contribute to economic and competitive success. Third, there is evidence of internal conflict within the Commission as to the relative importance of the Lisbon goals. Finally, the experience of distinct Member States presents challenges both for assessment and prescriptive remedies. The Commission has estimated that the cost of regulatory compliance obligations on businesses in the EU is between 4% and 6% of gross domestic product and that 15% of this figure is avoidable 'red tape' (the term used specifically to signify unnecessary compliance burdens). This article proposes to assess the likely outcomes of de-regulation as we rapidly approach 2010, the year for attainment of the Lisbon goals.

The corporate social responsibility movement and law's empire: Is there a conflict?

At the heart of corporate governance and social responsibility discourse is recognition of the fact that the modern corporation is primarily governed by the profit maximisation imperative coupled with moral and ethical concerns that such a limited imperative drives the actions of large and wealthy corporations which have the ability to act in influential and significant ways, shaping how our social world is experienced. The actions of the corporation and its management will have a wide sphere of impact over all of its stakeholders whether these are employees, shareholders, consumers or the community in which the corporation is located. As globalisation has become central to the way we think it is also clear that ‘community’ has an ever expanding meaning which may include workers and communities living very far away from Corporate HQ. In recent years academic commentators have become increasingly concerned about the emphasis on what can be called short-term profit maximisation and the perception that this extremist interpretation of the profit imperative results in morally and ethically unacceptable outcomes.1 Hence demands for more corporate social responsibility. Following Cadbury’s2 classification of corporate social responsibility into three distinct areas, this paper will argue that once the legally regulated tier is left aside corporate responsibility can become so nebulous as to be relatively meaningless. The argument is not that corporations should not be required to act in socially responsible ways but that unless supported by regulation, which either demands high standards, or at the very least incentivises the attainment of such standards such initiatives are doomed to failure. The paper will illustrate by reference to various chosen cases that law’s discourse has already signposted ways to consider and resolve corporate governance problems in the broader social responsibility context.3 It will also illustrate how corporate responsibility can and must be supported by legal measures. Secondly, this paper will consider the potential conflict between an emphasis on corporate social responsibility and the regulatory approach.4 Finally, this paper will place the current interest in corporate social responsibility within the broader debate on the relationship between law and non-legally enforceable norms and will present some reflections on the norm debate arising from this consideration of the CSR movement.

Non-product related environmental process and production methods (NPR-PPMs): a view from international trade law and international environmental governance

The primary aim of this thesis is to analyse legal and governance issues in the use of Environmental NPR-PPMs, particularly those aiming to promote sustainable practices or to protect natural resources. NPR-PPMs have traditionally been thought of as being incompatible with the rules of the World Trade Organization (WTO). However, the issue remains untouched by WTO adjudicatory bodies. One can suggest that WTO adjudicatory bodies may want to leave this issue to the Members, but the analysis of the case law also seems to indicate that the question of legality of NPR-PPMs has not been brought ‘as such’ in dispute settlement. This thesis advances the argument that despite the fact that the legal status of NPR-PPMs remains unsettled, during the last decades adjudicatory bodies have been scrutinising environmental measures based on NPR-PPMs just as another expression of the regulatory autonomy of the Members. Though NPR-PPMs are regulatory choices associated with a wide range of environmental concerns, trade disputes giving rise to questions related to the legality of process-based measures have been mainly associated with the protection of marine wildlife (i.e., fishing techniques threatening or affecting animal species). This thesis argues that environmental objectives articulated as NPR-PPMs can indeed qualify as legitimate objectives both under the GATT and the TBT Agreement. However, an important challenge for the their compatibility with WTO law relate to aspects associated with arbitrary or unjustifiable discrimination. In the assessment of discrimination procedural issues play an important role. This thesis also elucidates other important dimensions to the issue from the perspective of global governance. One of the arguments advanced in this thesis is that a comprehensive analysis of environmental NPR-PPMs should consider not only their role in what is regarded as trade barriers (governmental and market-driven), but also their significance in global objectives such as the transition towards a green economy and sustainable patterns of consumption and production.

A study of the extent to which Irish law, policy and practice allow for Ireland's application of the United Nations Convention on the Rights of the Child, 1989 to pre-natal children

The central research question of this thesis asks the extent to which Irish law, policy and practice allow for the application of the United Nations Convention on the Rights of the Child (CRC) to pre-natal children. First, it is demonstrated that pre-natal children can fall within the definition of ‘child’ under the Convention and so the possibility of applying the Convention to children before birth is opened. Many State Parties to the CRC have interpreted it as applicable to pre-natal children, while others have expressed that it only applies from birth. Ireland has not clarified whether or not it interprets it as being applicable from conception, birth, or some other point. The remainder of the thesis examines the extent to which Ireland interprets the CRC as applicable to the pre-natal child. First, the question of whether Ireland affords to the pre-natal child the right to life under Article 6(1) of the Convention is analysed. Given the importance of the indivisibility of rights under the Convention, the extent to which Ireland applies other CRC rights to pre-natal children is examined. The rights analysed are the right to protection from harm, the right to the provision of health care and the procedural right to representation. It is concluded that Ireland’s laws, policies and practices require urgent clarification on the issue of the extent to which rights such as protection, health care and representation apply to children before birth. In general, there are mixed and ad hoc approaches to these issues in Ireland and there exists a great deal of confusion amongst those working on the frontline with such children, such as health care professionals and social workers. The thesis calls for significant reform in this area in terms of law and policy, which will inform practice.

Narratives in early Irish law tracts

This thesis presents a study of the 112 narratives collected from the Corpus Iuris Hibernici. The selection of narratives is based on criteria informed by modern narratological theories. The significant presence of narratives in early Irish law tracts appears at odds with the normal conception of law texts as consisting solely of provisions, and therefore needs to be accounted for. Since no systematic study has been conducted of these legal narratives, this thesis serves as an introduction by giving firstly an index of narratives and secondly a categorisation of them in terms of distribution, dates and functions. It then carries out a general analysis of the relationship between legal narratives and early Irish literature, and a selected case study of the relationship between legal narratives and the legal institutions in the context of which the narratives are located. It has become clearer, with the progress of argument, that the use of narratives was an integral part of legal writing in medieval Ireland; and the narratives, though having many idiosyncratic features of themselves, are profoundly connected with the learned tradition at large. The legal narratives reveal the intellectual background and compositional concerns of medieval Irish jurists, and they formed a crucial part of the effort to accommodate law tracts into the dynamic tradition of senchas. Two appendices are included at the end: one consists of translations of 34 narratives from the index, and the other is a critical edition of one of the narratives discussed in detail, together with translations of some relevant passages.

The accountability of transnational armed groups under international law

Terrorist attacks by transnational armed groups cause on average 15,000 deaths every year worldwide, with the law enforcement agencies of some states facing many challenges in bringing those responsible to justice. Despite various attempts to codify the law on transnational terrorism since the 1930s, a crime of transnational terrorism under International Law remains contested, reflecting concerns regarding the relative importance of prosecuting members of transnational armed groups before the International Criminal Court. However, a study of the emerging jurisprudence of the International Criminal Court suggests that terrorist attacks cannot be classified as a war crime or a crime against humanity. Therefore, using organisational network theory, this thesis will probe the limits of international criminal law in bringing members of transnational armed groups to justice in the context of changing methods of warfare. Determining the organisational structure of transnational armed groups, provides a powerful analytical framework for examining the challenges in holding members of transnational armed groups accountable before the International Criminal Court, in the context of the relationship between the commanders and the subordinate members of the group.

[Book review] Psychology and Law: Truthfulness, Accuracy and Credibility

Review of: Psychology and law : truthfulness, accuracy and credibility by Amina Memon, Aldert Vrij and Ray Bull. London: McGraw-Hill, 1998.

Duty to mitigate in leasehold law

Discusses by reference to case law, including Commonwealth authorities, the rights and duties of landlords where demised premises are abandoned by a tenant who has defaulted on the rent, including the remedies available to the landlord, the limitations on his right to sue for loss of rent due between abandonment and expiration of the term, and the applicability of the contractual doctrine of mitigation of damages in leasehold law. Examines the Court of Appeal decision in Reichman v Beveridge on the duty of mitigate loss in an action merely seeking recovery of rent as it accrues due.

Termination of tenancies for tenant default: Law Commission's draft Bill

Reviews key proposals of a draft Bill set out in Command Paper: The Law Commission: Termination of Tenancies for Tenant Default (Cm.6946), aimed at replacing the existing law on forfeiture of tenancies. Summarises the main elements of the proposed termination action by landlords, the events justifying such an action, the time limits for serving default notices, the revised range of court orders available and the considerations influencing which type of order to make. Examines the position of qualifying interest holders and the circumstances in which summary termination notices are prohibited.