Generalized Derivations with Commutativity and Anti-commutativity Conditions

Let R be a prime ring with 1, with char(R) &#8800; 2; and let F : R &#8594; R be a generalized derivation. We determine when one of the following holds for all x,y &#8712; R: (i) [F(x); F(y)] = 0; (ii) F(x)&#927;F(y) = 0; (iii) F(x) &#927; F(y) = x &#927; y .</p

Dense Maritime Fog Attenuation Prediction from Measured Visibility Data

The benefits of Free Space Optics (FSO) motivate to use it for future high data rate demanding communication applications. However, widespread growth of the technology has been hampered by reduced availability due to weather influences on the link. The fog has been analyzed as the most detrimental for FSO communication. There are some models that predict fog attenuation in terms of visibility. These models are compared with measured attenuation data of dense maritime fog. The comparison has been in terms of Sum of Square Error (SSE) and Root Mean Square Error (RMSE). A new model has been proposed that gives the least SSE and RMSE for the measured data

Renew Cities to be the Engine of Growth

PIDE Cities Research Programme was initiated in Karachi with a conference titled Cities: the Engine of Growth on November 15-16, 2006. The conference was held in our largest city and was well-attended by economists, architects, town planners, Nazims, government officials, NGOs, journalists, and other citizens. The discussion was animated and about twenty-five speakers addressed the gathering. All points of view were represented and debated

The Effects of Weather on the Life Time of Wireless Sensor Networks Using FSO/RF Communication

The increased interest in long lasting wireless sensor networks motivates to use Free Space Optics (FSO) link along with radio frequency (RF) link for communication. Earlier results show that RF/FSO wireless sensor networks have life time twice as long as RF only wireless sensor networks. However, for terrestrial applications, the effect of weather conditions such as fog, rain or snow on optical wireless communication link is major concern, that should be taken into account in the performance analysis. In this paper, life time performance of hybrid wireless sensor networks is compared to wireless sensor networks using RF only for terrestrial applications and weather effects of fog, rain and snow. The results show that combined hybrid network with three threshold scheme can provide efficient power consumption of 6548 seconds, 2118 seconds and 360 seconds for measured fog, snow and rain events respectively resulting in approximately twice of the life time with only RF link

Bone Age practices in infants and older children among practicing radiologists in Pakistan: Developing world perspective

Objective To investigate which bone age assessment techniques are utilized by radiologists in Pakistan to determine skeletal age in three defined age groups: less than one year, one to three years and three to 18 years. We also assessed the perceived confidence in skeletal age assessments made by respondents using their chosen bone age assessment technique, within each defined age group. Materials and methods A cross-sectional survey was conducted among 147 practicing radiologists in Pakistan. A pre-validated survey form was adopted from a similar study conducted amongst members of the Society for Pediatric Radiology. The survey collected demographic information, choice of bone age assessment technique in each age group and confidence of bone age assessments in each age group. Results The hand-wrist method of Greulich and Pyle was used by 87.5% of respondents when assessing bone age in infants (less than one year), followed by Gilsanz-Ratib hand bone age method (7.3%). In children aged one to three years, Greulich and Pyle method was chosen by 85.7% of respondents, followed by Gilsanz-Ratib hand bone age method (6.1%) and the Hoerr, Pyle, Francis\u27 Radiographic Atlas of Skeletal Development of the Foot and Ankle (3.1%). In children, older than three years, the Greulich and Pyle technique was used by 83.7% of respondents. This was followed by Gilsanz-Ratib hand bone age method (5.8%) and the Hoerr, Pyle, Francis\u27 Radiographic Atlas of Skeletal Development of the Foot and Ankle (3.8%). 26.4% were very confident in bone age assessments conducted among infants. In children aged one to three years, 38.1% were very confident . In children, greater than three years, 48.6% were very confident in their chosen technique. Conclusion Greulich and Pyle is the dominant method for bone age assessments in all age groups, however, confidence in its application among infants and young children is low. It is recommended that clear recommendations be developed for bone age assessments in this age group alongside incorporation of indigenous standards of bone age assessments based on a representative sample of healthy native children

Assessment of menisci and ligamentous injuries of the knee on magnetic resonance imaging: correlation with arthroscopy

OBJECTIVE: To evaluate the validity of MRI, in the assessment of the meniscal and cruciate ligamenteous injuries of the knee joint and comparison with arthroscopic findings. METHODS: A one year prospective cross-sectional study from January 2006 to January 2007, was performed on 50 patients (32 males & 18 females) with knee injury presenting at the orthopedic unit of AKUH. The patients were referred to radiology department for MRI evaluation and arthroscopy. RESULTS: The sensitivity, specificity and accuracy for MRI of the menisci and ligaments were as follows: medial meniscus resulted in 100% sensitivity, 69.27% specificity, 90% PPV, 100% NPV and 92% accuracy: lateral meniscus resulted in 87.5% sensitivity, 88.23% specificity, 77% PPV, 93% NPV and 88% accuracy: anterior cruciate ligament resulted in 86.67% sensitivity, 91.43% specificity, 81% PPV, 94% NPV and 88% accuracy; posterior cruciate ligament resulted in 100% sensitivity, 95.83% specificity,50% PPV, 100 NPV and 96% accuracy. CONCLUSION: Magnetic resonance imaging is a good, accurate and non invasive modality for the assessment of menisci and ligamenteous injuries. It can be used as a first line investigation in patients with soft tissue trauma to knee

Cutaneous Squamous Cell Carcinoma, an Immunohistological Analysis

Background: To detect the presence of keratin in apparently non-keratinizing squamous cell carcinomas by immunoperoxidase staining. This is important because keratinizing tumours are less radiosensitive and non-keratinizing are more radio responsive. Methods: This prospective study was conducted at King Edward Medical College and Post Graduate Medical Institute, Lahore over six months, A total of 45 patients suffering from squamous cell carcinomas of skin were included in the study.Both H and E and immunoperoxidase stainings were performed. Positive and negative controls were set up. The results of both types of staining were compared for each case. Results: Four groups were identified. Nineteen cases showed obvious keratinization on both H and E and immunoperoxidase staining.Eight cases had doubtful keratinization on H and E but showed more obvious keratinization on immunoperoxidase staining. Seven cases were non-keratinizing on H and E staining but revealed keratin on immunoperoxidase analysis.Eleven cases were non-keratinizing on H and E as well as on immunoperoxidase analysis. Conclusion: Immunohistological technique can help us in revising and modifying our H and E impression of a squamous cell carcinoma. It can help us in better diagnosis of squamous cell cancers on basis of keratinizatio

The validity of observational measures in detecting optimal maternal communication styles: Evidence from European Americans and Latinos

This study examined the sensitivity of an observational coding system for assessing positive and negative maternal behaviors of Latino and European American mothers toward their adolescent children. Ninety Latino (54 Spanish speaking and 35 English speaking) and 20 European American mother-adolescent dyads participated in an observational study of conversations about sexuality, AIDS, and conflicts. Associations were examined between observed maternal positive and negative behaviors and adolescent-reported relationship quality. Results indicated that maternal negative responsiveness was negatively associated with relationship quality for all ethnic/language groups. However, maternal positive responsiveness was related to relationship quality for European Americans but not for Latinos. These findings suggest a need for a broader definition of positive parenting in Latino families. © Copyright © 2007, Society for Research on Adolescence.postprin

SK2 channels are required for function and long-term survival of efferent synapses on mammalian outer hair cells

Cochlear hair cells use SK2 currents to shape responses to cholinergic efferent feedback from the brain. Using SK2-/- mice, we demonstrate that, in addition to their previously defined role in modulating hair cell membrane potentials, SK2 channels are necessary for long-term survival of olivocochlear fibers and synapses. Loss of the SK2 gene also results in loss of electrically driven olivocochlear effects in vivo, and down regulation of ryanodine receptors involved in calcium-induced calcium release, the main inducer of nAChR evoked SK2 activity. Generation of double-null mice lacking both the α10 nAChR gene, loss of which results in hypertrophied olivocochlear terminals, and the SK2 gene, recapitulates the SK2-/- synaptic phenotype and gene expression, and also leads to down regulation of α9 nAChR gene expression. The data suggest a hierarchy of activity necessary to maintain early olivocochlear synapses at their targets, with SK2 serving an epistatic, upstream, role to the nAChRs.Fil: Murthy, Vidya. Tufts University; Estados UnidosFil: Maison, Stéphane F.. Massachusetts Eye and Ear Infirmary; Estados Unidos. Harvard Medical School; Estados UnidosFil: Taranda, Julian. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Tufts University; Estados UnidosFil: Haque, Nadeem. University of Notre Dame; Estados UnidosFil: Bond, Chris T.. Oregon Health Sciences University; Estados UnidosFil: Elgoyhen, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Adelman, John P.. Oregon Health Sciences University; Estados UnidosFil: Liberman, M. Charles. Massachusetts Eye and Ear Infirmary; Estados Unidos. Harvard Medical School; Estados UnidosFil: Vetter, Douglas E.. Tufts University; Estados Unido

Maternal obesity during pregnancy and premature mortality from cardiovascular event in adult offspring : follow-up of 1 323 275 person years

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