454 research outputs found

    Anonymous and Adaptively Secure Revocable IBE with Constant Size Public Parameters

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    In Identity-Based Encryption (IBE) systems, key revocation is non-trivial. This is because a user's identity is itself a public key. Moreover, the private key corresponding to the identity needs to be obtained from a trusted key authority through an authenticated and secrecy protected channel. So far, there exist only a very small number of revocable IBE (RIBE) schemes that support non-interactive key revocation, in the sense that the user is not required to interact with the key authority or some kind of trusted hardware to renew her private key without changing her public key (or identity). These schemes are either proven to be only selectively secure or have public parameters which grow linearly in a given security parameter. In this paper, we present two constructions of non-interactive RIBE that satisfy all the following three attractive properties: (i) proven to be adaptively secure under the Symmetric External Diffie-Hellman (SXDH) and the Decisional Linear (DLIN) assumptions; (ii) have constant-size public parameters; and (iii) preserve the anonymity of ciphertexts---a property that has not yet been achieved in all the current schemes

    Revocable IBE Systems with Almost Constant-size Key Update

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    Identity-based encryption (IBE) has been regarded as an attractive alternative to more conventional certificate-based public key systems. It has recently attracted not only considerable research from the academic community, but also interest from the industry and standardization bodies. However, while key revocation is a fundamental requirement to any public key systems, not much work has been done in the identity-based setting. In this paper, we continue the study of revocable IBE (RIBE) initiated by Boldyreva, Goyal, and Kumar. Their proposal of a selective secure RIBE scheme, and a subsequent construction by Libert and Vergnaud in a stronger adaptive security model are based on a binary tree approach, such that their key update size is logarithmic in the number of users. We ask the question of whether or not the key update size could be further reduced by using a cryptographic accumulator. We show that, indeed, the key update material can be made constant with some small amount of auxiliary information, through a novel combination of the Lewko and Waters IBE scheme and the Camenisch, Kohlweiss, and Soriente pairing-based dynamic accumulator

    Growth media derived from solid waste for orchid Dendrobium kingianum culture

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    Food waste and diaper waste contribute to top three ranking solid wastes in Malaysia. Many studies show that urine and food waste can be used as plant fertilizer but less attention has been given to the recycling of used diaper. Therefore, this study was conducted to formulate Dendrobium kingianum growing media by utilizing diaper waste and selected food waste: banana peels, coffee waste and eggshells. The chemical composition in diaper waste and food waste were determined by using ICP-OES method. Biochar derived from oil palm waste, sugarcane and sawdust were tested to reduce and neutralize the high ammonium content from diaper waste. Biochar derived from oil palm waste showed the best reduction of ammonium in diaper waste. Survival and growth performance of Dendrobium kingianum was observed and recorded. Results show that orchid in diaper formulated growth media T3 showed the best adaptation and growth performance with highest percentage of healthy leaves and number of absorption roots within 3 weeks observation period. These results revealed that diaper waste could be recycled as orchid growing media by formulating with food waste and biochar

    Optimal anticoagulation in elderly patients with atrial fibrillation: Which drug at which dose?

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    Aging is an important risk factor for adverse events in elderly patients with atrial fibrillation (AF) and complicates the management of anticoagulation. Underuse of oral anticoagulants (OACs) is  common in elderly patients because of comorbidities, the altered physiological function of multiple organs, frailty, risk of falls, and the lack of randomized controlled trials (RCTs) specifically for elderly patients. Nevertheless, current data still support OACs use for reducing ischemic stroke with positive net clinical benefits. Sub-analyses of RCTs and real-world cohort studies showed that non-vitamin K antagonist OACs (NOACs) would be more favorable choices compared to warfarin for stroke prevention in the elderly. This review will discuss important data on stroke prevention and the use of NOACs in elderly AF patients

    Massive haemorrhagic pericardial effusion as the cardiac manifestation of Salmonella enteritidis infection in a severely immunocompromised patient

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    A 41-years-old gentleman was admitted for reduced effort tolerance with non-specific symptoms of weight loss and generalised body weakness. Chest X-ray (CXR) showed cardiomegaly. Echocardiography showed a large pericardial effusion with septation. Emergency pericardiocentesis was performed and pericardial fluid culture grew Salmonella enteritidis (S. enteritidis). He tested positive for the retroviral disease, with a CD4 count of 10 cells/µL. Intravenous (IV) ceftriaxone was administered. A pericardial drain was inserted due to the rapid re-accumulation of pericardial fluid after the initial pericardiocentesis. He also had drainage of his left pleural effusion. He had a guidewire exchange of pericardial drain around 2 weeks after admission, with flushing performed whenever the flow was poor. A repeat echocardiogram showed early signs of constrictive pericarditis with residual pericardial effusion in which intrapericardial fibrinolysis was considered. He was started on antiretroviral therapy (ART) and his condition remained stable. The pericardial drain was kept throughout his admission. Unfortunately, he developed severe sepsis and succumbed to it about a month post-admission

    Multi-Modality Imaging of Atheromatous Plaques in Peripheral Arterial Disease: Integrating Molecular and Imaging Markers

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    Peripheral artery disease (PAD) is a common and debilitating condition characterized by the narrowing of the limb arteries, primarily due to atherosclerosis. Non-invasive multi-modality imaging approaches using computed tomography (CT), magnetic resonance imaging (MRI), and nuclear imaging have emerged as valuable tools for assessing PAD atheromatous plaques and vessel walls. This review provides an overview of these different imaging techniques, their advantages, limitations, and recent advancements. In addition, this review highlights the importance of molecular markers, including those related to inflammation, endothelial dysfunction, and oxidative stress, in PAD pathophysiology. The potential of integrating molecular and imaging markers for an improved understanding of PAD is also discussed. Despite the promise of this integrative approach, there remain several challenges, including technical limitations in imaging modalities and the need for novel molecular marker discovery and validation. Addressing these challenges and embracing future directions in the field will be essential for maximizing the potential of molecular and imaging markers for improving PAD patient outcomes

    A review and reflection on online learning and assessments in higher education after the pandemic

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    The 2020 COVID-19 pandemic has pushed many higher education institutions to deliver courses using online mode due to the movement restrictions. However, many academicians were under-prepared. Now that the pandemic is over, it is time to reflect on these online teaching practices and consider their suitability and sustainability in this post-pandemic era. This study used a case study approach and examined blended and hybrid learning and online assessments and their use in higher education institutions. It adopted a crowdsourcing approach to gather the relevant literature and was backed by the reflection and experience of the academicians in a branch campus of an Australian university in Malaysia. This study suggests that academicians could still use blended and hybrid learning as an alternative but must upskill themselves. Furthermore, selective online assessments could still be used. This study would be helpful to academicians and policymakers in higher education when deciding the teaching mode and assessments in the post-pandemic era

    Quality of life among undergraduate university students duringCOVID-19 movement control order in Sarawak

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    Background and Aims: The aim of this study was to examine the QoL and health satisfaction of undergraduate university students in Sarawak during MCO and its association with socio-demographic profiles. Methods: In this cross-sectional study, QoL and satisfaction of health of 503 undergraduate university students (63.4% females) from a public university was assessed online using the World Health Organization Quality of Life (WHOQOL)-BREF instrument. Results: The overall QoL and satisfaction with health were 3.7 ± 0.87 and 3.9 ± 0.82, respectively. Male students showed significantly lower mean scores for the environmental domains than female students (63.37 ± 16.21 vs 68.10 ± 14.00, p<0.01). Students who lived inside the campus (vs outside campus) showed significantly lower mean score for the physical health (61.49±13.94 vs 67.23±13.93, p<0.01), environmental health (58.35±15.07 vs 70.49±13.21, p<0.01), overall QoL (3.39±0.90 vs 3.84±0.83, p<0.01) and satisfaction with health (3.71±0.90 vs 3.97±0.77, p<0.01). Students with parent’s income below RM5000 (vs parent’s income more than RM5000) had significantly lower mean score for the environmental domain (65.06±14.35 vs 68.20±15.74, p<0.05). Others ethnicity scored significantly lower than Bumiputera Sarawak and Malay while Bumiputera Sarawak scored significantly lower than Chinese in physical health domain (Malay = 65.73±13.40, Chinese = 63.24±15.35, Bumiputra Sarawak = 67.35±13.30, Others = 60.84±15.88, p<0.05). Malay (69.99 ± 15.20) scored the significantly higher than other ethnicities (Chinese = 63.58 ± 15.80; Bumiputera Malaysia = 65.23 ± 13.66; others = 63.98 ± 15.59) in environmental domain (p<0.01). When comparing between religions, the results also showed there were significant differences between different religion groups in overall quality of life (Islam=3.75±0.93, Christianity=3.77±0.79, Others=3.34±1.14, p<0.05), physical health (Islam=65.00±13.86, Buddhism=68.40±11.99, Christianity=64.77±14.94, Others=61.00±16.03, p<0.05) and environmental health (Islam=69.66±15.48, Buddhism=64.99±11.36, Christianity=64.87±15.61, Others=62.13±16.28, p<0.05). Conclusion: By understanding university students’ QoL in this global disaster, relevant authorities would provide a better rehabilitation and assistance to those affected ones

    What is at stake in a war? A prospective evaluation of the Ukraine and Russia conflict for business and society

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    War produces devastating impacts on humankind, especially in terms of lives and livelihoods. While war is a widely studied topic in history, it remains relatively understudied in business. To address this gap, this article explores the impact of war for business and society. To do so, this article undertakes a prospective evaluation of the Ukraine and Russia conflict as a recent case of war. In doing so, this article reveals that a war can impact society within (e.g., limit access to basic necessities and monetary resources, increase unemployment and reduce purchasing power, and increase asylum seekers and refugees) and outside (e.g., supply shortage and inflation and threat of false information) as well as business within(e.g., threat of cyberattacks, threat to digital and sustainable growth, and short-term and long-term sanctions and support) and outside (e.g., test of business ethics and moral obligations and test of brand management) war-torn countries. The article concludes with an agenda for future research involving war, business, and society
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