Export performance and potential of Singapore

The growth of Singapore as a city started only in the nineteenth century when Sir Stamford Raffles landed there in search of a commercial centre for the (British) East India Company which acquired the whole island in 1824. The island had then only a few traders and fishermen. Shortly, however, it became an important trading and also an administrative centre first for the Straits Settlement, and later also for the Malay States. For its rapid subsequent growth Singapore had literally nothing but: (a) a good port in a good location, on the crossroads of the seas; (b) free port status; (c) a higher degree of security than prevailed in the region (provided by the British power). These meagre assets proved quite adequate to produce an important commercial centre. Until a few years ago Singapore was nothing but an entrepot trade base. Traders of many nations have found it convenient to use Singapore for receiving and handling goods in transit from, and to, all parts of the world, but especially goods moving in the region. This entrepot trade involves buying, e.g., various grades of rubber in small lots from various small producers or traders in the area, putting the lots together, grading them, packing them, and then re-exporting them to any part of the world. For many years, and even now, the local handling of those materials was slight so that the value added per dollar of sales was also slight. The volume of such trade was very high, however, and this gave the island its economic viability. The other element of this entrepot trade consisted in the practice of Singapore merchants buying manufactured goods in large lots in the advanced countries and then breaking-down these lots into small ones convenient for the small business firms in the whole of Southeast Asia, but especially the Malay Peninsula and Indonesia.

1H MR Spectroscopy in Gliomatosis: Is there a Sensitivity Issue?

Objective. 1H MR spectroscopy (MRS) is widely performed for assessment of brain tumours and is considered a highly sensitive technique capable of differentiating benign from malignant conditions and tumour grading. Method. We present a case of a 69 year old woman who was suspected to have gliomatosis on MRI. Results. MRS performed using single voxel and chemical shift/multivoxel techniques was within normal limits. A repeat scan 6 months later showed progressive disease, and biopsy was performed that proved the diagnosis of glioblastoma. Conclusion. Normal MRS in a patient with suspicion of gliomatosis on MRI should not reassure clinicians into assuming a benign aetiology or a good prognosis in short term

Absence of the suprarenal segment of the inferior vena cava with a coexisting absence of the right brachiocephalic vein in a 22-year-old Caucasian male with arterial hypertension

Congenital anomalies of the inferior vena cava (IVC) are rarely observed malformations of the venous system, occurring in 0.3% of otherwise healthy individuals, and in 0.6% to 2% of patients with coexisting cardiovascular defects. They are usually asymptomatic and recognised incidentally during imaging, operations or dissection studies. In this paper we report an extremely rare case of a 22-year-old Caucasian male, admitted for the purpose of excluding secondary causes of hypertension. During imaging of the abdomen and the thorax we found a complete lack of the suprarenal segment of the IVC, with a coexisting absence of the right brachiocephalic vein. We discuss the problem of congenital defects of the IVC and we review the relevant literature

Ribs of Pinna nobilis shell induce unexpected microstructural changes that provide unique mechanical properties

The reinforcement function of shell ribs depends not only on their vaulted morphology but also on their microstructure. They are part of the outer layer which, in the case of the Pinna nobilis bivalve, is built from almost monocrystalline calcitic prisms, always oriented perpendicular to the growth surfaces. Originally, prisms and their c-axes follow the radii of rib curvature, becoming oblique to the shell thickness direction. Later, prisms bend to reach the nacre layer perpendicularly, but their c-axes retain the initial orientation. Calcite grains form nonrandom boundaries. Most often, three twin disorientations arise, with two of them observed for the first time. Nano-indentation and impact tests demonstrate that the oblique orientation of c-axes significantly improves the hardness and fracture toughness of prisms. Moreover, compression tests reveal that the rib area achieves a unique strength of 700 MPa. The detection of the specific microstructure formed to toughen the shell is novel.The work was supported by the Polish National Agency for Academic Exchange (grant PPI/APM/2018/1/00049/U/001) and the National Science Center (grant UMO-2018/29/B/ST8/02200). MS was supported by the European Union from the resources of the European Social Fund (Project No.WNDPOWR. 03.02.00-00-I043/16). AGC was funded by project CGL2017-85118-P of the Spanish Ministerio de Ciencia e Innovación

Changing classroom culture, curricula, and instruction for proof and proving: how amenable to scaling up, practicable for curricular integration, and capable of producing long-lasting effects are current interventions?

This paper is a commentary on the classroom interventions on the teaching and learning of proof reported in the seven empirical papers in this special issue. The seven papers show potential to enhance student learning in an area of mathematics that is not only notoriously difficult for students to learn and for teachers to teach, but also critically important to knowing and doing mathematics. Although the seven papers, and the intervention studies they report, vary in many ways—student population, content domain, goals and duration of the intervention, and theoretical perspectives, to name a few—they all provide valuable insight into ways in which classroom experiences might be designed to positively influence students’ learning to prove. In our commentary, we highlight the contributions and promise of the interventions in terms of whether and how they present capacity to change the classroom culture, the curriculum, or instruction. In doing so, we distinguish between works that aim to enhance students’ preparedness for, and competence in, proof and proving and works that explicitly foster appreciation for the need and importance of proof and proving. Finally, we also discuss briefly the interventions along three dimensions: how amenable to scaling up, how practicable for curricular integration, and how capable of producing long-lasting effects these interventions are

Synthesis, structural, DFT calculations and biological studies of rhodium and iridium complexes containing azine Schiff-base ligands

The reaction of [Cp*MCl2]2 (M = Rh/Ir) with N-Nʹ azine Schiff-base ligands (L1-L4) leads to the formation of mononuclear cationic half-sandwich complexes having the general formula [Cp*M(L)Cl]+ (1–8), (M = Rh/Ir and L = (2-hydroxy-4-methoxybenzylidene)2- pyridylamidrazone (L1), (2-hydroxybenzylidene)2-pyridylamidrazone (L2), (1-(2-hydroxyphenyl)ethylidene)2-pyridylamidrazone (L3) and (1-phenylethylidene)2-pyridylamidrazone (L4). All these complexes were isolated as their hexafluorophosphate salts and fully characterized by spectroscopic and analytical techniques. The molecular structure of complexes (1), (3), (4), (7) and (8) have been determined by single crystal X-ray crystallographic studies which displayed the coordination of the ligand to the metal in a bidentate N∩N fashion through nitrogen atom of pyridine and one azine nitrogen. The chemo-sensitivity activities of the complexes were evaluated against HT-29 (human colorectal cancer) cell line and non-cancer cell line ARPE-19 (human retinal epithelial cells) which revealed that the complexes are moderately cytotoxic to cancer cells over human cells although complex 5 was the most potent among all the compounds. Theoretical studies carried out using DFT and TD-DFT at B3LYP level shows good agreement with the experimental results

c- and N-myc Regulate Neural Precursor Cell Fate, Cell Cycle, and Metabolism to Direct Cerebellar Development

Separate murine knockout (KO) of either c- or N-myc genes in neural stem and precursor cells (NSC) driven by nestin-cre causes microcephaly. The cerebellum is particularly affected in the N-myc KO, leading to a strong reduction in cerebellar granule neural progenitors (CGNP) and mature granule neurons. In humans, mutation of N-myc also causes microcephaly in Feingold Syndrome. We created a double KO (DKO) of c- and N-myc using nestin-cre, which strongly impairs brain growth, particularly that of the cerebellum. Granule neurons were almost absent from the Myc DKO cerebellum, and other cell types were relatively overrepresented, including astroglia, oligodendrocytes, and Purkinje neurons. These findings are indicative of a profound disruption of cell fate of cerebellar stem and precursors. DKO Purkinje neurons were strikingly lacking in normal arborization. Inhibitory neurons were ectopic and exhibited very abnormal GAD67 staining patterns. Also consistent with altered cell fate, the adult DKO cerebellum still retained a residual external germinal layer (EGL). CGNP in the DKO EGL were almost uniformly NeuN and p27KIP1 positive as well as negative for Math1 and BrdU at the peak of normal cerebellar proliferation at P6. The presence of some mitotic CGNP in the absence of S phase cells suggests a possible arrest in M phase. CGNP and NSC metabolism also was affected by loss of Myc as DKO cells exhibited weak nucleolin staining. Together these findings indicate that c- and N-Myc direct cerebellar development by maintaining CGNP and NSC populations through inhibiting differentiation as well as directing rapid cell cycling and active cellular metabolism