545 research outputs found
Administrator\u27s role in helping school personnel handle problems of children associated with divorce
School administrators make effective decisions that can have important consequences. Many of these decisions involve children of divorce, who make up approximately twenty percent of the school enrollment (Drake, 1981 ). Traditionally, school administrators have responded to the growing number of personal, social, and behavioral problems in schools. According to Delaney, Richards, and Strathe ( 1984) by the year 1990, one-third of all students in our schools will be children of divorced parents. As more support services are needed. there is pressure to provide counseling to meet the needs of school children. The school is the place that can focus help. Schools can play a significant role in facilitating a child\u27s adjustment to divorce by providing a natural environment where professionals can give support and assistance (Delaney et. al, 1984). Teachers work most closely with these children, yet most teachers have no special training to understand the special problems caused by parental divorce. Without such understanding, teachers cannot effectively intervene. The schools primary function is instruction, but a child in a crisis cannot learn until school personnel recognize the crisis and take steps to ameliorate its effects
Hardware security design from circuits to systems
The security of hardware implementations is of considerable importance, as even the most secure and carefully analyzed algorithms and protocols can be vulnerable in their hardware realization. For instance, numerous successful attacks have been presented against the Advanced Encryption Standard, which is approved for top secret information by the National Security Agency. There are numerous challenges for hardware security, ranging from critical power and resource constraints in sensor networks to scalability and automation for large Internet of Things (IoT) applications.
The physically unclonable function (PUF) is a promising building block for hardware security, as it exposes a device-unique challenge-response behavior which depends on process variations in fabrication. It can be used in a variety of applications including random number generation, authentication, fingerprinting, and encryption. The primary concerns for PUF are reliability in presence of environmental variations, area and power overhead, and process-dependent randomness of the challenge-response behavior.
Carbon nanotube field-effect transistors (CNFETs) have been shown to have excellent electrical and unique physical characteristics. They are a promising candidate to replace silicon transistors in future very large scale integration (VLSI) designs. We present the Carbon Nanotube PUF (CNPUF), which is the first PUF design that takes advantage of unique CNFET characteristics. CNPUF achieves higher reliability against environmental variations and increases the resistance against modeling attacks. Furthermore, CNPUF has a considerable power and energy reduction in comparison to previous ultra-low power PUF designs of 89.6% and 98%, respectively. Moreover, CNPUF allows a power-security tradeoff in an extended design, which can greatly increase the resilience against modeling attacks.
Despite increasing focus on defenses against physical attacks, consistent security oriented design of embedded systems remains a challenge, as most formalizations and security models are concerned with isolated physical components or a high-level concept. Therefore, we build on existing work on hardware security and provide four contributions to system-oriented physical defense: (i) A system-level security model to overcome the chasm between secure components and requirements of high-level protocols; this enables synergy between component-oriented security formalizations and theoretically proven protocols. (ii) An analysis of current practices in PUF protocols using the proposed system-level security model; we identify significant issues and expose assumptions that require costly security techniques. (iii) A System-of-PUF (SoP) that utilizes the large PUF design-space to achieve security requirements with minimal resource utilization; SoP requires 64% less gate-equivalent units than recently published schemes. (iv) A multilevel authentication protocol based on SoP which is validated using our system-level security model and which overcomes current vulnerabilities. Furthermore, this protocol offers breach recognition and recovery.
Unpredictability and reliability are core requirements of PUFs: unpredictability implies that an adversary cannot sufficiently predict future responses from previous observations. Reliability is important as it increases the reproducibility of PUF responses and hence allows validation of expected responses. However, advanced machine-learning algorithms have been shown to be a significant threat to the practical validity of PUFs, as they can accurately model PUF behavior. The most effective technique was shown to be the XOR-based combination of multiple PUFs, but as this approach drastically reduces reliability, it does not scale well against software-based machine-learning attacks. We analyze threats to PUF security and propose PolyPUF, a scalable and secure architecture to introduce polymorphic PUF behavior. This architecture significantly increases model-building resistivity while maintaining reliability. An extensive experimental evaluation and comparison demonstrate that the PolyPUF architecture can secure various PUF configurations and is the only evaluated approach to withstand highly complex neural network machine-learning attacks. Furthermore, we show that PolyPUF consumes less energy and has less implementation overhead in comparison to lightweight reference architectures.
Emerging technologies such as the Internet of Things (IoT) heavily rely on hardware security for data and privacy protection. The outsourcing of integrated circuit (IC) fabrication introduces diverse threat vectors with different characteristics, such that the security of each device has unique focal points. Hardware Trojan horses (HTH) are a significant threat for IoT devices as they process security critical information with limited resources. HTH for information leakage are particularly difficult to detect as they have minimal footprint. Moreover, constantly increasing integration complexity requires automatic synthesis to maintain the pace of innovation. We introduce the first high-level synthesis (HLS) flow that produces a threat-targeted and security enhanced hardware design to prevent HTH injection by a malicious foundry. Through analysis of entropy loss and criticality decay, the presented algorithms implement highly resource-efficient targeted information dispersion. An obfuscation flow is introduced to camouflage the effects of dispersion and reduce the effectiveness of reverse engineering. A new metric for the combined security of the device is proposed, and dispersion and obfuscation are co-optimized to target user-supplied threat parameters under resource constraints. The flow is evaluated on existing HLS benchmarks and a new IoT-specific benchmark, and shows significant resource savings as well as adaptability.
The IoT and cloud computing rely on strong confidence in security of confidential or highly privacy sensitive data. As (differential) power attacks can take advantage of side-channel leakage to expose device-internal secrets, side-channel leakage is a major concern with ongoing research focus. However, countermeasures typically require expert-level security knowledge for efficient application, which limits adaptation in the highly competitive and time-constrained IoT field. We address this need by presenting the first HLS flow with primary focus on side-channel leakage reduction. Minimal security annotation to the high-level C-code is sufficient to perform automatic analysis of security critical operations with corresponding insertion of countermeasures. Additionally, imbalanced branches are detected and corrected. For practicality, the flow can meet both resource and information leakage constraints. The presented flow is extensively evaluated on established HLS benchmarks and a general IoT benchmark. Under identical resource constraints, leakage is reduced between 32% and 72% compared to the baseline. Under leakage target, the constraints are achieved with 31% to 81% less resource overhead
Brain macrophages in human cortical contusions as indicator of survival period
The aim of this study was to establish a morphologic time scheme with which cases of cerebral contusion with unknown survival periods can be dated. Our study of 275 cases was limited to qualitative and quantitative changes in macrophages. The appearance of macrophages and their distribution as well as their content of neutral fat, esterified cholesterol, erythrocytes, siderin, hematoidin, and ceroid were correlated with the survival period. For each cytologic criterium, the observation period, distribution-free limits of tolerance, and relative frequency of identification in different survival periods were determined, and the limits of confidence calculated. The findings permit the dating of trauma in cases with unknown survival periods. Moreover, the probability of this dating was calculated
Ophthalmologic Findings of Boucher-NeuhƤuser Syndrome
To report a case of Boucher-NeuhƤuser syndrome, which is an autosomal recessive disorder characterized by the triad of spinocerebellar ataxia, chorioretinal dystrophy, and hypogonadotropic hypogonadism. An 18-year-old man was seen for visual problems, which had been diagnosed as retinitis pigmentosa at the age of 12 years. His puberty was delayed. At 16 years of age, the patient experienced progressive deterioration of his balance and gait disturbance. Then he was referred to our clinic because Boucher-NeuhƤuser syndrome was suspected. He had no specific family history; his visual acuity was 0.04 in both eyes. We observed broad retinal pigment epithelium atrophy and degeneration in both fundi. Both fluorescein and indocyanine green angiography showed choriocapillaris atrophy in the posterior pole area and midperiphery. Macular optical coherence tomography showed thinning of the neurosensory retina. An electroretinographic examination showed no photopic or scotopic responses. The Boucher-NeuhƤuser syndrome should be included in the differential diagnosis of patients with retinitis pigment epithelium atrophy and degeneration
Growth of the adult goldfish eye. II. Increase in retinal cell number
The retinas of adult goldfish, one to four years of age, 4ā23 cm in length, were examined with standard paraffin histology to determine if new cells were being added with growth. Retinal cell nuclei were counted and the area of the retina was measured. An analysis of cell densities in various regions throughout the retina showed that the cells are distributed nearly homogeneously. The density (No./mm 2 of retinal surface) of ganglion cells, inner nuclear layer cells and cones decreases with growth, but the density of rods remains constant. Thus the rods account for a larger proportion of the cells in larger retinas. The total number of cells per retina increases: the ganglion cells from 60,000 to 350,000; the inner nuclear layer cells from 1,500,000 to 4,000,000; the cones from 250,000 to 1,400,000; the rods from 1,500,000 to 15,000,000. This increase in the number of retinal neurons implies the formation of even more new synapses, and suggests the adult goldfish retina as a model for both neuro- and synaptogenesis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50001/1/901760303_ftp.pd
Local regeneration in the retina of the goldfish
We have studied regeneration of the retina in the goldfish as a model of regenerative neurogenesis in the central nervous system. Using a transsclearal surgical approach, we excised small patches of retina that were replaced over several weeks by regeneration. Lesioned retinas from three groups of animals were studied to characterize, respectively, the qualitative changes of the retina and surrounding tissues during regeneration, the concomitant cellular proliferation, and the quantitative relationship between regenerated and intact retina. The qualitative and quantitative analyses were done on retinas prepared using standard methods for light microscopy. The planimetric density of regenerated and intact retinal neurons was computed in a group of animals in which the normal planimetric density ranged from high to low. Cell proliferation was investigated by making intraocular injections of 5-bromo-2ā²-deoxyuridine (BUdr) at various survival times to label proliferating cells and processing retinal sections for BUdr immunocytochemistry. The qualitative analysis showed that the surgery created a gap in the existing retina that was replaced with new retina over the subsequent weeks. The BUdr-labeling experiments demonstrated that the excised retina was replaced by regeneration of new neurons. Neuroepithiallike cells clustered on the wound margin and migrated centripetally, appositionally adding new retina to the old. The quantitative analysis showed that the planimetric density of the regenerated neurons approximated that of the intact ones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50080/1/480230209_ftp.pd
Spinocerebellar ataxia type 1 with multiple system degeneration and glial cytoplasmic inclusions
Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited progressive neurological disorder characterized by neuronal degeneration and reactive gliosis in the cerebellum, brainstem, spinocerebellar tracts, and dorsal columns. Multiple system atrophy is a sporadic progressive neurological disorder with degeneration and gliosis in the basal ganglia, cerebellum, brainstem, and spinal autonomic nuclei, and with argyrophilic glial cytoplasmic inclusions. We describe 4 members of a family with the SCAl mutation and a dominantly inherited progressive ataxia in which autopsy examination of 1 member showed neuropathological changes typical of multiple system atrophy, including glial cytoplasmic inclusions. In this patient, magnetic resonance imaging revealed marked brainstem and cerebellar volume loss and mild supratentorial generalized volume loss. Positron emission tomography with [ 18 F]fluorodeoxyglucose revealed widespread hypometabolism in a pattern found in sporadic multiple system atrophy and not in dominantly inherited olivopontocerebellar atrophy. Positron emission tomography with [ ll C]flumazenil revealed normal benzodiazepine receptor distribution volumes, similar to those seen in sporadic multiple system atrophy. Two other family members still living had similar changes in the imaging studies. The findings in this family suggest that the SCAl gene mutation can result in a disorder similar to multiple system atrophy, both clinically and neuropathologically.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50359/1/410390214_ftp.pd
Afferent influences on brain stem auditory nuclei of the chicken: Neuron number and size following cochlea removal
Prognostic models for identifying adults with intellectual disabilities and mealtime support needs who are at greatest risk of respiratory infection and emergency hospitalisation.
Among adults with intellectual disabilities (ID), problems with eating, drinking and swallowing (EDS), and an associated need for mealtime support, are common, with an estimated 15% of adults known to specialist ID services requiring mealtime support. We set out to identify which adults with ID who receive mealtime support are at an increased risk of and .
An exploratory, prospective cohort study was undertaken in the East of England. At baseline, structured interviews with the caregivers of 142 adults with ID and any type of mealtime support needs were used to gather information on health and support needs over the previous 12 months. These interviews were repeated at follow-up, 12 months later. The resulting dataset, covering a 24-month period, was analysed with logistic regression, using model averaging to perform sensitivity analysis, and backwards step-wise variable selection to identify the most important predictors.
Individuals with (in the first year of study), those who had and those with were most likely to have in the second year. Adults with and/or (fed mainly or entirely by a caregiver or enterally) were at increased risk of for EDS-related problems.
Our findings highlight the importance of carefully monitoring health issues experienced by adults with ID and EDS problems, as well as their eating, drinking and swallowing skills. However, the models developed in this exploratory research require validation through future studies addressing the EDS problems commonly experienced by adults with ID and their implications for health outcomes and quality of life. Further research into the relationship between epilepsy and EDS problems would provide much-needed insight into the complex relationship between the two areas.This paper presents independent research commissioned by the National Institute for Health Research (NIHR) under its Research for Patient Benefit (RfPB) programme (grant reference number PB-PG-0906-11098). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Simon R. White was supported by the Medical Research Council (Unit Programme number U105292687)
Distinct glutaminyl cyclase expression in EdingerāWestphal nucleus, locus coeruleus and nucleus basalis Meynert contributes to pGlu-AĪ² pathology in Alzheimerās disease
Glutaminyl cyclase (QC) was discovered recently as the enzyme catalyzing the pyroglutamate (pGlu or pE) modification of N-terminally truncated Alzheimerās disease (AD) AĪ² peptides in vivo. This modification confers resistance to proteolysis, rapid aggregation and neurotoxicity and can be prevented by QC inhibitors in vitro and in vivo, as shown in transgenic animal models. However, in mouse brain QC is only expressed by a relatively low proportion of neurons in most neocortical and hippocampal subregions. Here, we demonstrate that QC is highly abundant in subcortical brain nuclei severely affected in AD. In particular, QC is expressed by virtually all urocortin-1-positive, but not by cholinergic neurons of the EdingerāWestphal nucleus, by noradrenergic locus coeruleus and by cholinergic nucleus basalis magnocellularis neurons in mouse brain. In human brain, QC is expressed by both, urocortin-1 and cholinergic EdingerāWestphal neurons and by locus coeruleus and nucleus basalis Meynert neurons. In brains from AD patients, these neuronal populations displayed intraneuronal pE-AĪ² immunoreactivity and morphological signs of degeneration as well as extracellular pE-AĪ² deposits. Adjacent AD brain structures lacking QC expression and brains from control subjects were devoid of such aggregates. This is the first demonstration of QC expression and pE-AĪ² formation in subcortical brain regions affected in AD. Our results may explain the high vulnerability of defined subcortical neuronal populations and their central target areas in AD as a consequence of QC expression and pE-AĪ² formation
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