Perak sebelum dan selepas perang dunia kedua: satu analisis tentang nasionalisme orang Melayu

Rencana ini adalah satu kajian tentang perkembangan Nasionalisme Melayu di negeri Perak Sebelum dan Selepas Perang Dunia Kedua perjuangan politik atau Nasionalisme negara kita adalah dilakukan oleh orang-orang Melayu. Rencana ini adalah satu analisis yang mempamerkan pola pelakuan politik dan pertumbuhan nasionalisme Melayu di Perak. Analisisnya meliputi pemikiran, semangat, kesedaran dan tindakan politik. Penubuhan Madrasah Il lhya Assyarif di Gunung Semanggol telah menjadi medan memperjuangkan bidang agama, pendidikan, ekonomi dan politik. Madrasah ini dan madrasah-madrasah lain telah mencorakkan politik Malaysia. Pengaruh perjuangan rumpun Melayu di Indonesia turut mewarnai perjuangan politik di negeri ini. Selepas perang Perak menjadi medan politik Melayu,khususnya partai radikal Melayu seperti PKMM, API dan AWAS yang akhirnya melahirkan PUTERA di Taiping dalam tahun 1947. Pertubuhan lain yang tumbuh mulai 1946 ialah Perikatan Melayu Perak dan Persatuan Melayu Perak. Dua Pertubuhan ini menjadi kerabat UMNO. Walaupun UMNO ditubuhkan di Johor Bahru, tetapi memulakan operasinya di Perak, apabila Dato Bukit Gantang dilantik menjadi Setiausaha Agong UMNO yang pertama Biro politik UMNO yang ditugas merancang protes Malayan Union juga dianggotai oleh ahli UMNO dari Perak. Kelahiran PAS juga dapat dikatakan bermula dari penubuhan partai Hizbul Muslimin di Gunung Semanggol pada tahun 1948. Politik Melayu di Perak berubah mulai tahun 1950 dan apabila halajuang politik Melayu dapat dikenalpasti pengasingannya melalui kehadiran orang Melayu dalam UMNO, PAS, NAP dan gerakan sayap kiri Pengaruh Elit Tradisional juga turut berakhir dalam tahun 1950'an. Hal ini ternyata apabila Ghazali Jawi mengambilalih pimpinan UMNO Perak menggantikan Dato ' Panglima Bukit Gantang (Presiden NAP) yang gaga1 mengasingkan UMNO Perak dan UMNO Pusat. Selepas tahun 1959, gerak politik Melayu dapat dilihat dengan kehadiran orang Melayu dalam UMNO, PAS dan DAP. Perkembangan dari tahun 1945 - 1959 telah mewarnai politik orang Melayu di Perak

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Time-Varying Total Stiffness Matrix of a Rigid Machine Spindle-Angular Contact Ball Bearings Assembly: Theory and Analytical/Experimental Verifications

A lagrangian formulation is presented for the total dynamic stiffness and damping matrices of a rigid rotor carrying noncentral rigid disk and supported on angular contact ball bearings (ACBBs). The bearing dynamic stiffness/damping marix is derived in terms of the bearing motions (displacements/rotations) and then the principal of virtual work is used to transfer it from the bearing location to the rotor mass center to obtain the total dynamic stiffness/damping matrix. The bearing analyses take into account the bearing nonlinearities, cage rotation and bearing axial preload. The coefficients of these time-dependent matrices are presented analytically. The equations of motion of a rigid rotor-ACBBs assembly are derived using Lagrange's equation. The proposed analyses on deriving the bearing stiffness matrix are verified against existing bearing analyses of SKF researchers that, in turn, were verified using both SKF softwares/experiments and we obtained typical agreements. The presented total stiffness matrix is applied to a typical grinding machine spindle studied experimentally by other researchers and excellent agreements are obtained between our analytical eigenvalues and the experimental ones. The effect of using the total full stiffness matrix versus using the total diagonal stiffness matrix on the natural frequencies and dynamic response of the rigid rotor-bearings system is studied. It is found that using the diagonal matrix affects natural frequencies values (except the axial frequency) and response amplitudes and pattern and causes important vibration tones to be missig from the response spectrum. Therefore it is recommended to use the full total stiffness matrix and not the diagonal matrix in the design/vibration analysis of these rotating machines. For a machine spindle-ACBBs assembly under mass unbalnce and a horizontal force at the spindle cutting nose when the bearing time-varying stiffness matrix (bearing cage rotation is considered) is used, the peak-to-valley variation in time domain of the stiffness matrix elements becomes significant compared to its counterpart when the bearing standard stiffness matrix (bearing cage rotation is neglected) is used. The vibration spectrum of the time-varying matrix case is marked by tones at bearing outer ring ball passing frequency, rotating unbalnce frequency and combination compared to spectrum of the standard stiffness matrix case which is marked by only the rotating unbalnce frequency. Therfore, it is highly recomended to model bearing stiffness matrix to be a time-dependent