2,377 research outputs found
Lipid vesicles chaperone an encapsulated RNA aptamer.
The organization of molecules into cells is believed to have been critical for the emergence of living systems. Early protocells likely consisted of RNA functioning inside vesicles made of simple lipids. However, little is known about how encapsulation would affect the activity and folding of RNA. Here we find that confinement of the malachite green RNA aptamer inside fatty acid vesicles increases binding affinity and locally stabilizes the bound conformation of the RNA. The vesicle effectively 'chaperones' the aptamer, consistent with an excluded volume mechanism due to confinement. Protocellular organization thereby leads to a direct benefit for the RNA. Coupled with previously described mechanisms by which encapsulated RNA aids membrane growth, this effect illustrates how the membrane and RNA might cooperate for mutual benefit. Encapsulation could thus increase RNA fitness and the likelihood that functional sequences would emerge during the origin of life
Privacy Risk in Machine Learning: Analyzing the Connection to Overfitting
Machine learning algorithms, when applied to sensitive data, pose a distinct
threat to privacy. A growing body of prior work demonstrates that models
produced by these algorithms may leak specific private information in the
training data to an attacker, either through the models' structure or their
observable behavior. However, the underlying cause of this privacy risk is not
well understood beyond a handful of anecdotal accounts that suggest overfitting
and influence might play a role.
This paper examines the effect that overfitting and influence have on the
ability of an attacker to learn information about the training data from
machine learning models, either through training set membership inference or
attribute inference attacks. Using both formal and empirical analyses, we
illustrate a clear relationship between these factors and the privacy risk that
arises in several popular machine learning algorithms. We find that overfitting
is sufficient to allow an attacker to perform membership inference and, when
the target attribute meets certain conditions about its influence, attribute
inference attacks. Interestingly, our formal analysis also shows that
overfitting is not necessary for these attacks and begins to shed light on what
other factors may be in play. Finally, we explore the connection between
membership inference and attribute inference, showing that there are deep
connections between the two that lead to effective new attacks
Recommended from our members
Improved single-swab sample preparation for recovering bacterial and phage DNA from human skin and wound microbiomes.
BackgroundCharacterization of the skin and wound microbiome is of high biomedical interest, but is hampered by the low biomass of typical samples. While sample preparation from other microbiomes (e.g., gut) has been the subject of extensive optimization, procedures for skin and wound microbiomes have received relatively little attention. Here we describe an improved method for obtaining both phage and microbial DNA from a single skin or wound swab, characterize the yield of DNA in model samples, and demonstrate the utility of this approach with samples collected from a wound clinic.ResultsWe find a substantial improvement when processing wound samples in particular; while only one-quarter of wound samples processed by a traditional method yielded sufficient DNA for downstream analysis, all samples processed using the improved method yielded sufficient DNA. Moreover, for both skin and wound samples, community analysis and viral reads obtained through deep sequencing of clinical swab samples showed significant improvement with the use of the improved method.ConclusionUse of this method may increase the efficiency and data quality of microbiome studies from low-biomass samples
Recommended from our members
Microbial predictors of healing and short-term effect of debridement on the microbiome of chronic wounds.
Chronic wounds represent a large and growing disease burden. Infection and biofilm formation are two of the leading impediments of wound healing, suggesting an important role for the microbiome of these wounds. Debridement is a common and effective treatment for chronic wounds. We analyzed the bacterial content of the wound surface from 20 outpatients with chronic wounds before and immediately after debridement, as well as healthy skin. Given the large variation observed among different wounds, we introduce a Bayesian statistical method that models patient-to-patient variability and identify several genera that were significantly enriched in wounds vs. healthy skin. We found no difference between the microbiome of the original wound surface and that exposed by a single episode of sharp debridement, suggesting that this debridement did not directly alter the wound microbiome. However, we found that aerobes and especially facultative anaerobes were significantly associated with wounds that did not heal within 6 months. The facultative anaerobic genus Enterobacter was significantly associated with lack of healing. The results suggest that an abundance of facultative anaerobes is a negative prognostic factor in the chronic wound microbiome, possibly due to the increased robustness of such communities to different metabolic environments
Civil Society Organisations and Conflict Management: The Nigerian Experience
Intra-state violent conflicts have been on the rise in many states in recent years. Climate change has been negatively affecting available resources in many communities, and this contributes to the spate of unhealthy competitions and violent conflicts in many communities. This is further compounded by the increasing waves of terrorism. Nigeria is not spared of this experience. From North to South, East to West, violent conflicts have negatively impacted on public service delivery and business activities in the world largest community of blacks creating a drawback in the development stride in local communities and society at large. There have been attempts by successive governments to address the violent conflicts, but much of which have been through the use of government security agents, and since violence begets violence, the approach has not really resulted in positive peace required to create the right business clime for the people. Following this, civil society organisations stepped in with a view to filling the gap occasioned by governmentâs failure to effectively manage the situations. The various civil society organisations explored tools, from traditional religion, Christian religion and modern conflict resolution mechanism to intervene in the conflicts. This paper examined the roles of these organisations in conflict intervention in Nigeria.Key words: Civil society organisations, conflict, intervention, Nigerian experience, implication, public service delivery, business activitie
Is tepid sponging more effective than paracetamol at relieving fever in febrile children in hot tropical climates? A mini review
Background: Childhood fever remains a significant health problem because of the convulsion risk it poses to the child as well as the parental anxiety it provokes. Tepid sponging of such children remains commonplace in tropical climates despite the lack of evidence to support it.Objective: To evaluate the effectiveness of tepid sponging in hot tropical climatesMethods: NICE systematic review methodology was used. Medline and EMBASE were searched from their inception to date. Eligibility criteria included a) studies of randomised controlled trial (RCT) design b) children aged 2 to 120 months c) the use of tepid sponging alone in one arm and paracetamol in the other arm of the experiment. Eligible studies were critically appraised with NICE risk of bias tool. The outcome of interest was the number of afebrile children 2 hours after intervention. The outcome data from eligible studies were pooled for meta-analysis using random effects.Findings: Out of the 201 papers retrieved from the electronic search, two studies met the inclusion criteria. The meta-analysis found that tepid sponging was less effective than paracetamol at relieving fever two hours post-intervention (RR=0.25, 95% CI 0.08-0.79]).Conclusion: Tepid sponging was not effective against fever. There is the need to modify existing local clinical protocols to reflect the new evidence and international guidelines
Infrastructure for Peace: The African Experience
The study investigated experiences of infrastructures for peace mainly in Kenya and Ghana. It also explored experiences in other parts of Africa, and proceeded to argue a case for their creation in other climes in Africa. Standing peace structures have potentials to help promote peaceful business clime and other conditions necessary for human and societal development. Over the years, unhealthy competitions for limited resources in manâs environment and election triggered violence among others have been consistently increasing threats to peace and security as well as various business- related economic activities in many communities in Africa. There are attempts by Government at various levels to curtail the alarming rate of threats to through governmentsâ security apparatus, yet threats to peace remains. This informed the need to explore alternative approach. As a cutting-edge approach for violent prevention, conflict intervention and transformation, infrastructure for peace has been found rewarding in addressing conflicts and violent menace. This paper focused on two main examples of infrastructure for peace, which are cabinet-level Ministry of Peace and National or Local Peace Committee/Council. The study adopted a descriptive style and proceeds to propose what the role of a ministry of peace might be in Nigeria.Key words: Infrastructure, Peace, African, Experienc
Oxygen-isotope ratios in the Blue Glacier, Olympic Mountains, Washington, U.S.A.
The mean per mil deviation from a standard (average ocean water) in the O^(18)/O^(16) ratio of 291 specimens of ice, firn, snow, and rain from the Blue Glacier is â12.4; extremes are â8.6 and â19.2. This is consistent with the moist temperate climatological environment. The O^(18)/O^(16) ratio of snow decreases with declining temperature of precipitation, and it also decreases with increasing altitude at 0.5/100 meters.
Analyses of the three principal types of ice, coarse-bubbly, coarse-clear, and fine, composing lower Blue Glacier, show that ratios for coarse-clear ice are generally lower and for fine ice they are mostly higher than the ratios for coarse-bubbly ice. This indicates that the fine ice represents masses of firn and snow recently incorporated into the glacier by filling of crevasses or by infolding in areas of severe deformation. Coarse-clear ice masses may represent fragments of coarse-bubbly ice within a breccia formed in the icefall. Because of unfavorable orientation, these fragments could have undergone exceptional recrystallization with reduction in air bubbles and, possibly, a relative decrease in O^(18).
A longitudinal septum in the lower Blue Glacier is characterized by higher than normal O^(18)/O^(16) ratios. These values are consistent with an origin for this feature involving incorporation of much surficial snow and firn near the base of the icefall. Samples from longitudinal profiles on the ice tongue suggest that ice close to the snout comes from high parts of the accumulation area. Analyses from the light and dark bands of ogives are compatible with the concept that the dark bands represent greatly modified insets of firn-ice breccia filling icefall crevasses.
The range in ratios of materials is much greater in the accumulation area than in the ice tongue. This is attributed to homogenization, much of which takes place during the conversion of snow to glacier ice. This is supported by comparative analyses of snow layers when first deposited and months later, after alteration. Refreezing of rain and meltwater percolating into underlying cold snow is an important mechanism as shown by analyses of ice layers and lenses in the firn formed in this manner
Tumor Microenvironment Heterogeneity: A Review of the Biology Masterpiece, Evaluation Systems, and Therapeutic Implications
A tumor can be considered as a highly heterogeneous functional tissue, connected and dependent on the microenvironment, which sends and receives signals to and from the tumor tissue itself. Tumor cells alter the mechanical properties of the microenvironment in order to create favorable conditions for their proliferation. Stromal cells and nonâcellular elements of the extracellular matrix (ECM), including the host immune system, the fibrous scaffolding, the fundamental substance, and blood vascularization can determine tumoral cell morphologies, functions, aggressiveness, and response to treatment, as well as an accurate assessment of prognosis of the patients. Robust morphometric digital pathology techniques that are able to standardize measurements and analyse whole sets of immunohistochemical images are called for to identify, describe, and quantify the elements of the ECM. The computerâautomated segmentation algorithms are therefore required to increase the knowledge on the tumor microenvironment heterogeneity and to provide new therapeutic targets
KOINTEGRASI DAN ANALISIS VOLATILITAS CO-MOVEMENT PASAR MODAL DI 5 NEGARA ASEAN TAHUN 1988-2011
Pertumbuhan ekonomi yang fenomenal dari pasar modal di ASEAN-5 menarik perhatian para investor di pasar global. Pasar modal menjadi indikator kemajuan ekonomi sebuah negara sekaligus menjadi penunjang perekonomian (Robert Ang, 1997). Ketika ekonomi bergerak menuju liberalisasi, pergeseran dari kemandirian pasar menuju pasar yang ter kointegrasi. Penekanan yang kuat telah menempatkan pasar modal ASEAN-5 untuk ter kointegrasi dan memiliki interaksi antara pasar saham internasional dan regional sehingga dalam satu kawasan regional cenderung memiliki pergerakan volatilitas yang sama (volatility co-movement). Selama periode pengamatan, tahun 1988-2011, terjadi fenomena dimana pergerakan volatilitas pasar modal ASEAN dalam kawasan satu regional tidak selalu sama. Hal ini juga didukung oleh perbedaan yang ditemukan pada hasil beberapa penelitian terdahulu. Tujuan dari penelitian ini adalah untuk mengetahui hubungan kointegrasi jangka panjang pasar modal ASEAN, perbedaaan hubungan kointegrasi jangka panjang pasar modal ASEAN sebelum dan sesudah krisis tahun 1997, dan pergerakan volatilitas IHSG diantara pasar modal ASEAN yang lainnya seperti SET, PHSC, KLCI, dan STI.
Metode analisis yang digunakan dalam penelitian ini adalah VAR dengan menggunakan uji Johansen Cointegration Test, Granger Causality Test, dan GARCH(1,1); TARCH; EGARCH. Penelitian ini menggunakan data mingguan dari harga pasar saham 5 negara ASEAN, yaitu IHSG, KLCI, STI, PHSC, SET dari tahun 1988 sampai tahun 2011, dengan sumber data diambil dari Bloomberg
Hasil dari penelitian ini menunjukkan bahwa ada kointegrasi jangka panjang di pasar modal ASEAN dalam satu wilayah regional, kointegrasi jangka panjang pasar modal ASEAN-5 pasca krisis tahun 1997 semakin menguat dibandingkan sebelum krisis, pergerakan volatilitas IHSG diantara pasar modal ASEAN yang lain memiliki pergerakan yang cenderung bergerak kearah yang sama
- âŠ