2,179 research outputs found
Mediators of mechanotransduction between bone cells
Mechanical forces are known to regulate the function of tissues in the body, including bone. Bone adapts to its mechanical environment by altering its shape and increasing its size in response to increases in mechanical load associated with exercise, and by decreasing its size in response to decreases in mechanical load associated with microgravity or prolonged bed rest. Changes in bone size and shape are produced by a cooperative action of two main types of the bone cells - osteoclasts that destroy bone and osteoblasts that build bone. These cell types come from different developmental origins, and vary greatly in their characteristics, such as size, shape, and expression of receptor subtypes, which potentially may affect their responses to mechanical stimuli. The objective of this study is to compare the responses of osteoclasts and osteoblasts to mechanical stimulation.
This study has allowed us to conclude the following:
1. A mediator is released from a single source cell.
2. The response to the mediator changes with distance.
3. The value of the apparent diffusion coeficient increases with distance.
4. A plausible proposed mechanism is that ATP is released and degrades to ADP.
5. Future experiments are required to confim that ATP is the mediator as suggested
Parametric and Reliability Estimation of the Kumaraswamy Generalized Distribution Based on Record Values
A general family of distributions, namely Kumaraswamy generalized family of (Kw-G) distribution, is considered for estimation of the unknown parameters and reliability function based on record data from Kw-G distribution. The maximum likelihood estimators (MLEs) are derived for unknown parameters and reliability function, along with its confidence intervals. A Bayesian study is carried out under symmetric and asymmetric loss functions in order to find the Bayes estimators for unknown parameters and reliability function. Future record values are predicted using Bayesian approach and non Bayesian approach, based on numerical examples and a monte carlo simulation
DDoS Attack Detection Using Cooperative Overlay Networks and Gossip Protocol
DDoS attacks have major impact on the affected networks viz. packet transmission delays, network outage, website sabotage, financial losses, legitimate-user blockage and reputation damage. Existing DDoS detection techniques are either implemented at the victim node (but the damage is already done) or at many intermediate routers which run DDoS detection algorithms, that adds additional delay and more processing. We aim to detect DDoS attacks by using a new technique of cooperative overlay networks which overcomes the above problems by implementing the DDoS detection algorithm at one hop distance nodes (called defense nodes) from the victim.
DOI: 10.17762/ijritcc2321-8169.15062
Role of Private Sector in HIgher Education of Pakistan: Predicaments and Insights
The nationalization of industry and education in the early 1970s resulted in the deterioration of private sector with minimal investment in this field. This continued into late 90s with Pakistan recording comparatively low public spending on education as a percentage of GDP . Thus the government of Pakistan, in an effort to enhance intellectual capital and enrollments, established the Higher Education Commission (HEC) assigned to evaluate, improve and promote the higher education and research culture in both public and private sectors in Pakistan. Since its establishment in 2002, the HEC has “undertaken a systematic process of implementation of the five-year agenda for reform outlined in the HEC Medium Term Development Framework (MTDF) . Thus, with the inception of HEC, the number of private sector universities has surged from 25 (2001) to 53 (2010) and the private sector enrolments in higher education institutions increased from 43,873 a 15.8% of the total enrolment of 276,274 (2001) to 115,369 a 14% of the total enrolment which is 803,507(2009) .
The contribution of private sector has been criticized for not being aligned with the national priority paradigm or core strategic aims proposed by HEC in its Medium Term Development Framework 2005-2010 (MTDF). The MTDF stressed upon the importance of improving access to education; promoting excellence in learning and research; faculty development; and industrial linkages relevant to the economy .
Although HEC has granted charter to the private sector as “general institutes”, the focus of autonomous private sector institutions has remained on demand-led subjects producing graduates specifically in the fields of management sciences, medical, engineering and information technology. Also the expansion in the institutional capacity of private educational sector may not guarantee employability. Critics of private sector have always perceived its efforts delinked from government’s intention of enhancing the quality of research and growth in pure/basic disciplines of science, social sciences and humanities.
The purpose of this paper, therefore, is to analyze the strategic targets envisaged in the HEC Policy and Educational Reforms in Pakistan; to appreciate the participation of private sector institutions towards improving the access to higher education; to objectively evaluate its role and initiatives in the development of human capital suitable for national and international socio-economic milieu; and also to examine the contribution of private sector in promoting research culture. The paper concludes that HEC needs to revisit its strategies set out in the MTDF and introduce new guidelines for private sector in higher education
Free Textbook Distribution Process in Sindh, Pakistan: A Study of Stakeholders Perceptions
Placed amongst the lower middle income countries (The World Bank 2010), a large segment of the population of Pakistan is unable to afford the expenses on basic amenities including education. In year 2003, the Government of Sindh, initiated a free textbooks scheme.
This study investigates the transparency and efficiency of distribution process; examines the challenges and opportunities of the procurement and delivery process; and assesses the perceptions and feedback of the stakeholders. The study was conducted in all the districts of Sindh Province. The data were collected through analysis of documents, field survey, focus group discussions and interviews.
The study concluded that the scheme was marred by logistic and resource constraints, lack of coordination, weak management, capacity issues of functionaries, ineffective monitoring mechanism, institutional corruption, and intervention‘s sustainability. The paper recommends that the public education delivery mechanism needs to be revisited and updated
A reinforcement learning recommender system using bi-clustering and Markov Decision Process
Collaborative filtering (CF) recommender systems are static in nature and does not adapt well with changing user preferences. User preferences may change after interaction with a system or after buying a product. Conventional CF clustering algorithms only identifies the distribution of patterns and hidden correlations globally. However, the impossibility of discovering local patterns by these algorithms, headed to the popularization of bi-clustering algorithms. Bi-clustering algorithms can analyze all dataset dimensions simultaneously and consequently, discover local patterns that deliver a better understanding of the underlying hidden correlations. In this paper, we modelled the recommendation problem as a sequential decision-making problem using Markov Decision Processes (MDP). To perform state representation for MDP, we first converted user-item votings matrix to a binary matrix. Then we performed bi-clustering on this binary matrix to determine a subset of similar rows and columns. A bi-cluster merging algorithm is designed to merge similar and overlapping bi-clusters. These bi-clusters are then mapped to a squared grid (SG). RL is applied on this SG to determine best policy to give recommendation to users. Start state is determined using Improved Triangle Similarity (ITR similarity measure. Reward function is computed as grid state overlapping in terms of users and items in current and prospective next state. A thorough comparative analysis was conducted, encompassing a diverse array of methodologies, including RL-based, pure Collaborative Filtering (CF), and clustering methods. The results demonstrate that our proposed method outperforms its competitors in terms of precision, recall, and optimal policy learning
Fungal endophyte misidentified as Neurospora crassa.
The endophytic fungus isolate, ZP5SE, recently described in Rehman et al. 2008 was misidentified identified as Neurospora crassa. The 28S ribosomal gene sequence of the isolate shows 100% sequence similarity with GenBank accession Neurospora crassa M38154
NO2 and Humidity Sensing Characteristics of Few-layer Graphene
Sensing characteristics of few-layer graphenes for NO2 and humidity have been
investigated with graphene samples prepared by the thermal exfoliation of
graphitic oxide (EG), conversion of nanodiamond (DG) and arc-discharge of
graphite in hydrogen (HG). The sensitivity for NO2 is found to be highest with
DG. Nitrogen-doped HG (n-type) shows increased sensitivity for NO2 compared to
pure HG. The highest sensitivity for humidity is observed with HG. The sensing
characteristics of graphene have been examined for different aliphatic alcohols
and the sensitivity is found to vary with the chain length and branching.Comment: 19 pages, 7 figure
Single-chain Fv phage display propensity exhibits strong positive correlation with overall expression levels
<p>Abstract</p> <p>Background</p> <p>Single chain Fvs (scFvs) are widely applied in research, diagnostics and therapeutic settings. Display and selection from combinatorial libraries is the main route to their discovery and many factors influence the success of this process. They exhibit low thermodynamic stability, resulting in low levels of premature cytosolic folding or aggregation which facilitates <it>sec </it>YEG-mediated translocation and phage in <it>E. coli</it>. However, there is little data analysing how this is related to and influenced by scFv protein expression.</p> <p>Results</p> <p>We characterised the relationship between overall scFv expression and display propensity for a panel of 15 anti-tetanus toxin scFvs and found a strong positive correlation (Rho = 0.88, p < 0.005) between the two parameters. Display propensity, overall expression and soluble localisation to the periplasm and extracellular fractions were clone specific characteristics which varied despite high levels of sequence homology. There was no correlation between display of scFv or its expression in non-fused (free) form with soluble scFv localisation to the periplasm or culture supernatant. This suggests that divergence in the fate of scFv-pIII and non-fused scFv after translocation to the periplasm accounts for the observed disparity. Differential degrees of periplasmic aggregation of non-fused scFv between clones may affect the partitioning of scFv in the periplasm and culture supernatant abrogating any correlation. We suggest that these factors do not apply to the scFv-pIII fusion since it remains anchored to the bacterial inner membrane as part of the innate phage packaging and budding process.</p> <p>Conclusion</p> <p>We conclude that in the absence of premature cytosolic aggregation or folding, the propensity of a scFv to be displayed on phage is directly related to its overall expression level and is thus indirectly influenced by factors such as codon bias, mRNA abundance or putative DNA motifs affecting expression. This suggests that scFvs capable of high overall expression and display levels may not produce high yields of non phage-fused soluble protein in either the periplasmic or extracellular fractions of <it>E. coli</it>. This should be considered when screening clones selected from combinatorial libraries for further study.</p> <p>The nucleotide and amino acid sequences of the anti-tetanus toxin scFvs have been deposited in the EMBL data base: accession numbers-C1: <ext-link ext-link-type="embl" ext-link-id="AM749134">AM749134</ext-link>, C2: <ext-link ext-link-type="embl" ext-link-id="AM749135">AM749135</ext-link>, C3: <ext-link ext-link-type="embl" ext-link-id="AM749136">AM749136</ext-link>, C4: <ext-link ext-link-type="embl" ext-link-id="AM749137">AM749137</ext-link>, C5: <ext-link ext-link-type="embl" ext-link-id="AM749138">AM749138</ext-link>, N1: <ext-link ext-link-type="embl" ext-link-id="AM749139">AM749139</ext-link>, N2: <ext-link ext-link-type="embl" ext-link-id="AM749140">AM749140</ext-link>, N3: <ext-link ext-link-type="embl" ext-link-id="AM749141">AM749141</ext-link>, N4: <ext-link ext-link-type="embl" ext-link-id="AM749142">AM749142</ext-link>, N5: <ext-link ext-link-type="embl" ext-link-id="AM749143">AM749143</ext-link> J1; <ext-link ext-link-type="embl" ext-link-id="AM749144">AM749144</ext-link>, J2: <ext-link ext-link-type="embl" ext-link-id="AM749145">AM749145</ext-link>, J3: <ext-link ext-link-type="embl" ext-link-id="AM749146">AM749146</ext-link>, J4: <ext-link ext-link-type="embl" ext-link-id="AM749147">AM749147</ext-link>, J5: <ext-link ext-link-type="embl" ext-link-id="AM749148">AM749148</ext-link>.</p
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